hey
i'm in that situation too, i've found that its hard but it is v.manageable to eat healthily with only limited space, it just takes planning.
i buy things in small amounts a few times a week, like fresh fruit and veg, becaus it goes rotton before i have chance to eat it if i buy in bulk once a week. for breakfasts i have oatmeal with nuts, dried aprictos, prunes etc. in. all these things are cheap and dont go off very quickly.
oatmeal, brown rice, wholewheat pasta and cous cous make up my carbs pretty much, i also get cans of kidney beans and chick peas which last for ages and are good on a budget (about 30 pence a tin in england wahey!), frozen vegetables for quick easy things to go with meals and dried spices to make things taste nice
in the fridge i keep milk, cheese, jam sometimes, most other things i keep in my room or in my cupboard.
try making your own soup, its v.simple and i often make it and freeze it so it lasts the week.
thats all i can think of right now...but good luck.