Lets see, before you buy that new computer:
1 Remove everything from your start menu, you don't need all that junk loading.
2 See what is loading in background, ready to launch faster, because it's sucking up resources. Kill anything that you don't need.
3 Do you have a second drive (not a logical drive, a second physical drive) for your CS2 Temp files? It helps.
4 Memory. I missed how much you had. More is better.
5 And this one will make a significant difference!
Services.
Disable unnecessary services. 2000 and XP installs all sorts of things like Alerter. The less resources that these are taking up, the faster your system will operate.
Start>Programs>Administrative Tools>Services.
You'll need to tweak this yourself, and I'd suggest you write down what's there to start with.
If you don't see services, you need to go into start>settings>taskbar>startmenu (if classic) otherwise Control Panel, Start Menu and Taskbar applet. Either way, "Display Administrative Tools" needs to be checked.
6 If you want to speed up hard disk and slack space, get a raid-0 installed. (I wish I had it) Type 0 has no redundancy, it's not for backup or security, it's for speed. You'll basically have these drives for power and speed and then save anything onto your main system hard drive.
I only have a 2.2gHz Dell machine, 2gb memory, 140gb hard drive / 60 gb hard drive. (money is an issue!

) It loads CS2 a little slow, but once it's up and running, I don't have speed problems. I don't have all the services turned off on this one. So you should be able to go fast if you do all of the above.
One more small note. A 2.2 gHz laptop is not as fast as a 2.2 gHz desktop/tower. Your choice of a tower is the best for speed.
You don't need a $3000 computer to run CS2 or CS3, just one that is tweaked for speed. Oh by the way, mine was under $400 used, but I spent a few hundred on the hard drive, DVD writer and more memory. Still it was well under $700 total.