hi there,
i was having the same problem trying to find out about this damn mobo. eventually i gave up and called my supplier for the details. they told me that i have the IM845GL model although my manual says its the IM845GV. well anyway, ahe gave me the spec for the GL model. i have a celeron 2.6 running in my system and i was told that i could upgrade up to a P4 (no idea of top speed), 400 fsb and up to 256 L2 cache. the woman told me a load more crapwhich i never understood (because im useless with these things!) and im sure she didnt either! i dont think anything else is relevant to what your asking but if you want the rest of the details then feel free to email me.
i spoke to my mate who told me the mobo is pretty limited and i qoute "i wouldn't even wipe my arse with it!". so do what i did, sell the thing and get yourself a decent board, there are some real cheap budget boards out there with high end spec!
anyway, hope this was of some help!