help: pregnant and terrible diet


so I'm in a situation where I'm having to stay with my boyfriends sister. I'm dependant on her for a home, car, food. the problem I am having is she buys nothing but very unhealthy food to eat. canned food, ramen noodles, mac n cheese, pizza. and if she does cook its filled with things I don't like and her cooking is just awful and it really stresses me out. today I got my food stamps and so she took me to go buy food. I was excited to finally buy healthy food and food I actually like. she was curious to what I planned on buying and I told her I was going to buy fruits and veggies and meats to cook dinners with so me and the baby can eat better.. she said well don't buy too much of that because we need food that will last, buy some canned food and more ramen. I told her the nicest way possible that I really need to start eating healthier for my baby. canned food and ramen are very high in sodium and it makes my blood pressure very high and gives me terrible nasty heartburn. but she says I cant afford to be eating healthy. I'm worried about the health of me and my baby on this terrible diet. its really pissing me off. and I don't know what to do. in a little over a month I should be getting on WIC and I'm so happy that they have healthy and organic options. not crap like this woman is trying to have me eat :( I've been staying with her for 2 weeks and before then my blood pressure was always normal.