Most notebooks have little upgrade capacity beyond adding more memory or changing the hard drive.
Which OS are you running ?
A 650 cpu with that kind of RAM should be more than capable.
The best programmer I've ever know still does most of her work on one of a matched pair of 450 mhz notebooks. She upgraded the memory from 64 to 128mb recently and the 6gb hard disks are beginning to nag as possible upgrades, but her output is incredible.
Playing DVD to TV is always a bit of a chore, at least in my experience. Most systems default back to 800x600 low res output to TV and often stutter and stammer along.
Depending on the OS there could be lots of things you could do to tune and tweak. If you're running 2000 or have upgraded to XP could you also confirm whether or not your disk is FAT or NTFS.