Yeah, I would get her to the vet as soon as possible. Lots of vets work with their clients to form some sort of payment plan if you are unable to pay in full at one time.
If she is pregnant - she should go to the vet to make doubly sure that she is and get a checkup, blood work done, everything. Also they'll do x-rays, depending on far along she is just to see how the babies look and check how many there are.
And if it's not pregnancy - she still needs to go to the vet to checked out and see what's causing the bloating in her stomach. Plus, this will be a good time to go and ahead and get her spayed, get her shots, etc.
I've never dealt with a pregnant cat nor been around for the birthing. I've only always rescued abandoned day old kittens or 2-4 week old kittens. *sigh*
If she is, indeed, pregnant.....the vet there will probably have lots of papers and advice for how to deal with everything. They'll probably even have some books or websites to recommend to you.