IMVU Won't Run on my Mac

I recently (yesterday) got a second-hand Mac desktop from my mother. I am pretty lost, considering I’ve been a PC user for years; I haven’t used a Mac since middle school or earlier. I’m also not that tech-savvy to begin with, so please forgive my complete & total ignorance in this.

My biggest issue is that I am an avid IMVU (Instant Messaging Virtual Universe), and so the first thing I did was download it. But when I tried to run it, I got a message reading “You cannot use the application “IMVU” with this version of Mac OS X.” However, according to the IMVU FAQs, the only requirements are, “Individuals must have a personal computer (PC or Mac) and broadband access to use IMVU.” I did find a post on the IMVU forums saying that IMVU had updated their minimum system requirements, though. It says the requirements for Macs as of May 27th, 2011 are:

2 GB RAM

Intel Core 2 Duo

Intel GMA 950 video card

It took me only a bit of Googling to figure out that I needed to click on the Apple logo, then on “About this Mac.” This is what I got:

Mac OS X

Version 10.5.2

Processor 2 GH Intel Core 2 Duo

Memory 1 GB 667 MHz DDR2 SDRAM

Startup Disk Macintosh HD

As far I can figure out, that means I have the “Intel Core 2 Duo,” but not the “2 GB RAM,” and I can’t figure out about the video card one way or the other.

I also found a topic that seems similar on here: https://discussions.apple.com/thread/1425687?start=0&tstart=0

I tried a couple of the suggestions, but it was very slow going, like working through a high school math problem in 5^th grade. (As I mentioned, I am basically computer illiterate.) Nothing I tried worked, and before I go spending another 3+ hours trying the rest, I guess I’d just like to know: is it even possible to run IMVU on this computer? Is there anything I can do or anything I can purchase to make it possible?

Also: I found a topic on here with another user trying to run IMVU on a Mac, and the answer given read, “If your absolutely most importat issue is gaming, then you're probably better off with a PC.” And another person complained that they were able to download it, but it lags like mad. Is this true? Should I just stop trying to run IMVU with this computer?

Please help, and thanks in advance for your time!