First, you really should wet sand those rusted areas right now and primer them to prevent further damage to your ride.
Second, since you don't have much budget to play with, visit a few paint shops in the area (MAACO included), and ask them if you can see some of their recently painted cars. Check out their quality for yourself based on actual observation, not just a few opinions. Ask them to give you quotes for the different types of paint jobs.
Third, maybe you can do the masking/wet sanding yourself if you have experience in that area. Ask the paint shop if they accept cars that have been masked/sanded by the customer. Check out some books/websites on DIY auto painting.
Lastly, maybe there is a local college that has an automotive tech department that will paint your car for free as a project.
2004 E60 530is, Delivered 12/12/03, TiSilver/LGrey, PP, SP,PS, PDC, ACC, FRS, Step, Xenons, clear bra, body colored rear inserts. (Retired, 1983 henna red 320is)
2004 Corvette Z06 Commemorative Edition