Rob,
I see this is your 1st post with us. Welcome to HomeRecording - it's a great place. I'm no audio expert, but I've been into computers off and on since I was a kid...(i.e. checking out my Dad's original XT w/ 10MB HDD that cost him over $1k extra!) ;-)
Three things. One: I'm going to assume that when you mean broke, it means not much money at all - so I will not suggest a new computer as others might. I am positive you can get this to work - but it may be slow.
Two: The suggestion to use Kristal as your sequencing software is a good one. It has a small footprint (the entire app is only like 3.5MB download!), is free, and actually pretty good w/ low resource usage. You can download it here:
http://www.kreatives.org/kristal/index.php?section=download
Three: Your hardware - you might like to know some of this.
Others may disagree, but I feel the K6 back in 1997, was AMD's first real push at Intel. Sure, I remember seeing AMD 386 chips and such back in the day, but the K6 really marks some decent X86 architecture from a competitor, not just a copied chip. For the first time, an AMD "in house" design could actually compete w/ an Intel design...thus the beginnning of the good old fashioned rivalry.

If yours is runing at 500MHz, I think you have a K6-III+ cpu. That's a good thing - it's similar to a low end Pentium III. It will run XP just fine.
What is limiting you here is your RAM. Big time. You want at least 256MB to do anything really smoothly. Some of us freak out if we use a machine w/ less than 2GB ram these days.

But I think you could score some really cheap, used of course. Please let me know 2 things when you reply:
1. Where do you live? Do you have a Craigslist or Ebay type thing open to you?
2. Please go here
http://www.cpuid.com/cpuz.php and download the CPU-Z 1.49 file (it is small and won't install anything on your computer, it will just run a quick utility). Once CPU-Z has loaded, see exactly which processor you have, and then click the tab for RAM. Please report back with the RAM type, speed, how much is in each slot and if you have any slots free. I am sure for less than the cost of a couple burgers you can get some more, but we need to know specifics.
There is hope...let us know,
Jed