HG1995: Ok, I found MSI Radeon R7 265 OC 2GB $179 AUD. Not sure if it needs extra power adapter. Some cards seem to need extra power for the overclocked version.
A few options for gtx 750 ti cards.
MSI GeForce GTX 750 Ti Gaming 2GB $189 AUD could be a tight fit, just need to move hdd.
Should just miss Memory slots.
EVGA GeForce GTX 750 Ti $189 AUD. Only 6.7” long.
Gigabyte GeForce GTX 750 Ti OC 2GB $179 AUD. Minimum power 400W
ASUS ATI HD7750 V2 PCI-E 3.0, 1GB 128-bit GDDR5 $109AUD
Leaning towards the MSI GeForce GTX 750 Ti or EVGA GeForce GTX 750 Ti.
Or the R7 265. Not sure on which on to go for?
Mainly playing old games but some newer ( Witcher 2, Batman Arckham City) hoping for very slight improvement.
Thanks for all the quick answers
The R7 265 is 150W TDP. That Thermaltake "power supply" is more fire hazard than power supply and absolutely must be replaced to run a card like that. It's a much better performer and definitely the better deal at those prices.