150-160$ gpu & gts 450

Hi there, I would like to ask what GPU would be the best choice for gaming to someone that has a range of 150-160$ budget? I am currently using GeForce GTS 450 and some games don't run as good as I'd like to. Maybe a second 450 would be a better choice than a brand new GPU? Also, if I decide to buy a brand new one should I look for a specific one like, ASUS, EVGA, MSI and so on? what are the differences between those? And the last question, when should someone start worrying about GPU burning, at how many celsius it becomes dangerous for a GPU to keep running?

Thanks in advance! 

I have that card and it kicks ass.

Usually, the GPU will start to freak out at 90C. But if it does reach 80C, precautionary measures must be taken to avoid the GPU reaching higher temperatures. For example, increase the fan speed to about 70%, that's the most tolerable dB I find. Any higher than that will make me go nuts.

For long-term measures, make sure you have adequate air flow inside your case; like have positive air flow that won't be too little or too much for your system. Clean out the insides, especially the video card, as more dust inside could cause the GPU to overheat. Do this every year to avoid having big chunks of dust inside your case, like those ones that you might've seen on the internet.

If you like Nvidia you can't go wrong with this card. But I would go with the 6870. It's a beast.

Thanks for responses guys, you've helped me out a lot!

i have installed msi afterburner..on my msi gt780 laptop..i run about 70 degrees on my gpu...i have to ask ..is that too hot or is it average?