Ghia's with different rims.....

Hey if anyone can help me let me know. I need to know how wide of
tires I can go in a 1974 coupe ghia. I want to go 15 x 7, with low
profile tires. Is there going to be any rubbing of the tires on the
wheel wells in front when I turn or in the rear. If you know please
reply. Also if anyone knows of a cheap mail order rim company let
me know.
Thanx in advance for any help given.
Lance.