Dell :: Replacing The Video Card In My Old 9300. What's Compatible

I had originally planned on just building a seperate desktop, but had recieved some interesting offers on here and seen some things on ebay that made me reconsider breathing a bit more life into this laptop.

I have an older Inspiron 9300, that originally came with a 6800go (256mb). What other cards can I put in it that will a) fit and b) perform well, without c) needing major modifications (new battery, etc, etc)?

I know the 6800go will, and the x300, but what about the 7300go that was put in the e1505s and Inspiron 6400s a generation later? Do the heatsinks and stuff line up still, or are they the wrong size?

Any advice or links would be appreciated. Also, if someone has a part they'd like to sell, or links to places they can be found for cheap, feel free to hit me up in-thread with those as well.