I've got the same bike- Silver. Best parts source is Ebay. Challenge items to find are 6volt bulbs and good body pieces. I have had good luck finding everything I've needed (and I've needed plenty) but you need to be patient- it'll eventually turn up on ebay!
Most important thing to get is the parts diagram with the part numbers. I have one in soft copy so PM me with your email address and I'll send you a copy as well as a soft copy of a manual. Parts from the F7-C won't necessarily fit the F7A, etc, but some F7 parts will fit the F6 and the 250 & 350 models. Always check part numbers before buying.
They're fun little bikes, but they were lots faster back when I was 14 and weighed 120 pounds!
A couple of pointers- Do Not run it without a battery! The engine will run fine, but the battery provides storage for excess power from the charging system- Otherwise you'll get to replace every single bulb on the bike like I did!
If you have any specific questions just shoot me a message. Have fun.
1980 Vespa P200E