You would probably be able to get a system that runs those games with decent settings for 1200 canadian dollars I my self am buying a new computer and I found the best way to research is to start with all the parts and ask and look at reviews.
The new intel processers are amazing but expensive as it sounds like you dont have alot of money to spare i would go with a AMD Athlon AM2 processor as they are usually much cheaper but do not give you the same performance.
My friend just bought a pretty sweet setup
Here are the stats as far as I know:
AMD Athlon64 AM2 2.0 GHz
Ram two Gigs of Geil pc6400 800mhz 4-4-4-15
430 watt extreme coolermaster PSU
Aspire X-discovery case(lights
250g hard drive 7200RPM Sata2
I would get one with at least one PCI-E as all good video cards play on PCI-E (they go twice as fast as aGP cards)
Nvidia 7600GT decent card but at the rate games are coming up I would spend an extra $30-$50 to get a 7900Gs
now the information iam giving you doesnt mean you rely on it i can alyways be wrong
as i said reviews on the internet from reliable sites are helpful and reading forums aree definitly the way to go if you want to learn