Compaq V2606CU CPU Upgrade

Hello, I'm interested in upgrading my old laptop. I don't want anything spectacular out of it, just to make it better for little investment. Then my kids can use it.

It is a Compaq V2606CU with AMD Mobile Sempron 3000+ 1.8Ghz CPU, 1.5GB 333 DDR memory, XP Home OS, and I replaced the hard drive (80 GB) within the last 6 months.

Currently, it is used to access the internet, check email, and play young kids (7 and 9 yrs old) games online. My kids use it for schoolwork too. Basically, it is very slow. It sometimes takes a long time to open windows/files, especially just after start up/log on. It seems to be slow loading pages on the web too. Occasionally it will lock up for several seconds, maybe even a minute, when the kids see it is slow to respond and keep re-opening a window.

Like I said, I want to upgrade to make it faster. I've been looking at maxing it to 2GB in memory, which will cost $25-30. But I've also been wondering about replacing the CPU. Everything I've researched says it is a socket 754. I believe the early Turion mobile cpu's will work. I saw an ML-37 for $29 on ebay. This is 2Ghz but is 64-bit. Would operating at 32-bit slow it down? I know I could also get the latest Sempron or Athlon socket 754, but I don't think they are that much cheaper on ebay.

I would like to speed it up with the minimum amount of investment. So like less than $30 for cpu or memory, whichever gives the most return. I have 3 newer computers, but am nostalgic about this one and would like to keep it longer, especially if I can improve it cheaply.
Thanks