Word of advice. When you get your next computer, make sure that it does not say Dell, Compaq, Hewlett Packard, or any other name brand on it. Name brand computers tend to be built with the specific purpose of destroying any chance of upgrading you might have. You often find that they are small and cramped, with like 2 useable PCI slots, and no AGP slot. Before buying hardware for your computer, make sure that someone who knows stuff about computers looks it over.
Since you are buying memory, I will tell you this. Your computer takes PC-66 SDRAM. PC-100 SDRAM will
likely work as well. But whatever you buy, make sure that it is backwards compatable to PC-66. Some memory manufacturers make memory that craps out if it runs too slow. Your computer can have a maximum of 512MB of memory, but you only have two memory slots. You can put a maximum of 256MB of memory in one slot. If you buy a 256MB stick, it should work alongside your existing 64MB stick, giving you a total of 320MB of memory. That should be a good chunk of memory for any computer. (my computer is about twice as fast as yours and only has 256MB, but I am thinking of upgrading soon, as memory is cheap, and I need more memory for programming purposes)
If you decide to buy a new video card, take note that you CANNOT use an AGP video card. This seriously limits your options, and I don't know how many modern video cards (if any) actually support PCI. Make sure that you ask the clerk about their PCI cards, and not their AGP cards when you go in. Make it clear to them that you do not have an AGP slot. When you install your video card, you will have to disable your onboard card. To do that, follow
these instructions.
Oh, and for god's sakes, get rid of that blasted ME. Your computer has enough problems without using that crap. Find someone with a copy of Windows 95 or something. Your best option would be Windows 98 SE.
EDIT: I did some checking, and a Radeon 7500 LE seems to be available in PCI. I would advise getting that card, as it is about the best performer that you are likely to find that's available in PCI. It's not a powerhouse, but it should get the job done, and can be had for a fairly cheap price. It's about equivalent to a GeForce 2 in power.