"I am a big fan of you" or "I am a big fan of yours"?
Solution 1:
'...big fan of yours' is both the usual expression, and is the correct form as well. The former is likely incorrect.
http://forum.wordreference.com/showthread.php?t=561802 (response by xhalli).
http://www.english-test.net/forum/ftopic14888.html
Solution 2:
The latter '...big fan of yours' is certainly the usual expression. But I see no reason why you shouldn't say '...fan of you' if you want to. It is not ungrammatical.