Welcome to the coffee shop Heather!
I wanted a stock look, so used same tire all around. I went with what I found the largest that fit WELL on the front - 215 70 14. If the link works right this should show the comparison to what you are running now.
Tire Size Comparison
As for the back, Ramie
@straightlinespeed just did his, not sure what sizes. I know he did big back small front, but I believe was running 15's. There is also a wheels and tires thread that could be very helpful.
Keith