If you want a successful semester then put in the time and effort needed to make good grades in your physics and chemistry class. Don't slack off or get complacent because the first test or whatever might not be too hard or you made an A on it. So just work hard at it and seek help if you are struggling with a concept.
As far as paying for school I'm under the impression that most people take out loans. I am planning on looking into a potential military route because I know they will pay for PA and CRNA school but I'm doubting they will cover AA school as of now even though the profession is recognized by the federal government and the fact that you can work in VA hospitals. But more then likely I will be taking out loans to cover my expenses.
I took both the GRE and MCAT and I would say do both if you can afford it but if not I would just take the MCAT. The MCAT is a tougher test and I imagine it looks better if you only had one of them. Besides schools like CASE and UMKC (?) only take the MCAT while I think other programs allow the MCAT to substitute in place of the GRE. And obviously I would apply to all the programs to increase your chances of getting in some where and not being set on UMKC.
Hopes this helps and good luck.