That is indeed a difficult thing to go through, with the pressure from your husband and all,
and someone who i am very very close to has gone through something very similar, she got her tubes tied from being pressured not just by her husband, but also her in-laws, and it tormented her conscience for i think about 20 years or so, because she tried asking many priests “was this a mortal sin?” and trying to find out what to do, and she could never get a straight yes or no answer, until finally, about 2 or 3 years ago, she found a good priest from the priestly fraternity of saint peter, and he was able to give her a straight answer, that yes it was a mortal sin, and so she confessed it, and was absolved, and she’s just been alot better since then.
so, yes you can become a catholic no problem, and since there is nothing you can do about it for lack of money, i would just recommend talking to your priest about it.