lol no.
A .ahf file is not really a "film", it's not a movie file. It just contains the data so the AH film viewer (which is actually a kind of stripped-down version of the game) can re-create the events on your screen. And simply renaming a file doesn't change it's very nature.
You have to make a movie first before uploading - you have to capture (="film") the action on your screen by using a capture program like FRAPS, then edit the film with a program like the Windows Movie Maker, Sony Vegas or similar editing software