House Hunting sooo much fun

We have really started to out grow our little but not so little two bedroom duplex.. i love it i have a yard a basement a garage its great.. its just two bedrooms though. so i love living in valmeyer and i love the school and/or monroe county schools.. so i do not want to move form the county. i would rather not move from my little town at all. we have an apt to go look at two story spacious three bedroom house for rent her in my town yay!!! but the only catch is the rent is very steep... like 3 hundred more than what we pay here! yikes and not to mention its a two story two and half bath so my utlities will prolly go up as well. but it was built only two years ago so its a little more effeicent i'm sure. plus i can deal with windows open and space heaters a little to cut back on costs.. i know how be thirfty but damn i don't want to be strugglin in the winter when the tattoo shp slows down.. but its rent with opition to buy which is awesome since our credit needs some work and it gives us alittle time to get things in order..which is perfect for us right now. it has the space we need really bad.. i'm just really on the fence about it. i'm scared of bitting of more than i can chew.. baby will be here in july so we are going to cramped.. can't get a homeowner loan just yet.. and i can't really find too many rental propeties in my area or that are much cheaper any way.. pretty much going rate for any 3 bedroom or bigger house is about the same in rent anywhere........ aaaaaaaaaaahhhhhhhhhh i'm confused..... Help need advice please!!!