Well, to be honest that advent should play WoW at ultra fine if you knock the shadows down one notch (experimental doesnt look any better really but hurts framerate big time in my experience), the lower res screen on the machine will help keep it 'versatile' a lot longer, my desktop 4870 was 40-60+ with these settings at 1920x1200, and although I stopped playing WoW, when I had my M17 with dual 4850 mobiles, they were faster than my 4870 was.
WoW is also very CPU limited, so you could also buy an OEM/ES processor off ebay and fit that to improve your experience, your budget would allow you to pick up either an X9100 QS (2x 3.06Ghz) or a Q9300 (4x 2.53). Both will run warmer but nothing that wouldnt be liveable, as long as you were careful and put on decent thermal paste well
Modern Warfare 2 again should be fine. The 4850m is equivalent to a 4830, and thats still perfectly adequate at 1440x900, same as the 4850/70 at 1680x1050 and 1920x1200.
Only thing I'd mention is take off the stock drivers ASAP, and then download new drivers and get them mobility modded, the newer 9.8 Hotfix, 9.8 or 9.9 drivers will probably be 6 months or so newer than the machine default drivers!
Part of the problem you have with your 2x8700GT as well is that WoW generally doesn't work well with SLI, it doesnt cause major issues most of the time, but it doesnt really make use of the second card (even the devs have acknowledged this). So the likelyhood is you're basically running on a single 8700GT (desktop 8600), which would be why Ultra kills your system so bad.
The 4850m should be a lot faster, hell the 4670 would likely be faster than that.
Will go take a look at that HP for you
