There's a place in Cranford New Jersey called "Hobby Heaven" that sells most of the supplies you might need. They have a website if you're too far to drive, I've ordered from them before and was satisfied with their service. If you live near a "Pep Boys" auto parts store go there and get a can of "PlastiKote #T-235" sandable primer; it works with 99.9% of all model plastics or if you can find Tamiya's primer I've heard that it works well because of it's formula
Good luck and happy modelling!!!