I totally agree with Katie, it's best to keep her in as an indoor cat at least until you get the money to have her spayed. Letting such a young cat get pregnant isn't wise, and it'll be traumatic for her when she's just a baby herself. Get a litter tray and position it somewhere where snow can have privacy, once she starts going you shouldn't have a problem with her peeing anywhere else. Make sure she has plenty of toys and things to keep her occupied and then she won't pine to go out if she ever starts to.
If you can't afford toys you do'nt have to buy them, a scrumpled up piece of paper on a bit of string is fine, bottle caps, a russtling object, cats don't have to have posh toys. Or a cardboard box with holes cut out of the side and you can poke things through for her to investigate, she'll love it probably.

It's best all round for Snow's happiness and welfare that she's kept in and kept busy, with a litter tray and some food and you should have one pretty content cat!

Kate, Jack & Sunny xx