These quotes make me second guess everything...
He wishes to establish the devotion to My Immaculate Heart throughout the world. I promise salvation to whoever embraces it; these souls will be dear to God, like flowers put by Me to adorn his throne.
My Immaculate Heart will be your refuge and the way that will lead you to God.
To prevent this, I shall come to ask for the consecration of Russia to my Immaculate Heart…
Just the whole salvation through her makes me suspicious… or am I reading this wrong?
Yeah Fatima is extremely questionable for exactly the reasons you state, seems rather like something made up by someone wishing to exploit the excessive Marian devotion common at the time.
Why not ask to have Russia dedicated to Jesus’ heart? Why not Jesus’s heart as our refuge?
This and other dubious happenings (like Lucia claiming she saw the guardian angel of Portugal

) makes the whole affair quite fishy.
Because Jesus wants it this way. One should read the official documents of Fatima to gain the proper understanding of this.
These are the same questions some priests involved with Fatima asked of Lucia. And she asked God for answers and He gave them:
Sister Lucia wrote of the apparition of 10 December 1925, referring to herself in the third person:
The Most Holy Virgin appeared to her [Sister Lucia], and by her side, elevated on a luminous cloud, was the child Jesus. The Most Holy Virgin rested her hand on her [Sister Lucy’s] shoulder and as she did so, she showed her a heart encircled by thorns, which she was holding in her other hand. At the same time, the Child said:
Have compassion on the Heart of your Most Holy Mother, surrounded with thorns with which ungrateful men pierce it at every moment, and there is no one to make an act of reparation to remove them.
… in August of 1931, at a chapel in Rianjo, Spain, Sister Lucia reported this important revelation to her bishop:
My confessor ordered me to inform Your Excellency about what happened a little while ago, between our Good God and myself: As I was asking God for the conversion of Russia, Spain and Portugal, it seemed that His Divine Majesty said to me:
You console Me a great deal in asking Me for the conversion of those poor nations:* Request it also of My Mother**, while
saying to Her often: Sweet Heart of Mary, be the salvation of Russia, Spain, Portugal, Europe and the whole world.
At other times say: By Thy Pure and Immaculate Conception, O Mary, obtain for me the conversion of Russia, Spain, Portugal, Europe and the whole world.
Make it known to My ministers, given that they follow the example of the King of France in delaying the execution of My command, they will follow him into misfortune. It is never too late to have recourse to Jesus** and Mary**.* (said Jesus)
The efforts on the part of the religious persons involved to better understand the requests from God form a part of Fatima’s history. Upon conveying these requests, Sister Lucia was asked questions from the bishops, and, …at the first available opportunity she would ask Jesus or Blessed Mary through prayer. **One such question dealt with the number of first Saturdays. **On 29 May 1930, at a chapel in Tuy, Spain, Sister Lucia through prayer asked, ‚Why five Saturdays and not 9, or 7, in honor of the Sorrows of Our Lady?‛
Through an interior locution from Jesus, Sister Lucia said she was given to understand that this related to the five main types of offences committed against the Immaculate Heart of Mary: blasphemies against the Immaculate Conception; against Mary’s perpetual Virginity; against her Divine Maternity and the refusal to recognize her spiritual motherhood of mankind; for the offences of those who encourage in the hearts of children indifference, contempt and even hatred of their Immaculate Mother, and finally as reparation for those who outrage her in her holy images.
According to Sister Lucia, Jesus further stated:
There, My daughter, is the reason why the Immaculate Heart of Mary inspired Me to request this small act of reparation, and in consideration of it, to move My mercy to forgive souls who have had the misfortune to offend Her. As for you, seek unceasingly, through your prayers and sacrifices, to move My mercy with regard to these poor souls.
Questions were also asked about the form of the consecration of Russia to the Immaculate Heart of Mary. On 18 May 1936, Sister Lucia replied by letter to Father Jose Goncalves, her spiritual director:
I have spoken with Our Lord about the subject, and not too long ago I asked Him why He would not convert Russia without the Holy Father making that consecration. Jesus answered, ‘
Because I want My whole Church to acknowledge that consecration as a triumph of the Immaculate Heart of Mary so that it may extend its cult later on and put the devotion to this Immaculate Heart beside the devotion to My Sacred Heart.’
Selections from the book
A While Longer, pages 54-57.
amazon.com/While-Longer-Greg-J-Cring/dp/1463562543/ref=sr_1_1?ie=UTF8&qid=1329097683&sr=8-1
An excellent book covering the details, including official Church documents, on Fatima is the 480 page definitive work:
fatimafamily.org/store/index.php?main_page=product_info&products_id=42
God bless you.