Overheating GPU

[precursoris]

I had a Nvidia GT 220 which died out due to overheating. With it the idle temperature of the GPU was in the mid 70 C.

Now I have installed a GTS 250(with 100% fan speed). It's idle temp was 54 C, but I opened up the computer and blew out all the dust from the grills and fan of the cpu heatsink unit. After I did this, I booted the computer and it had a GPU temp of 43 C. But 2 minutes later, its temp increased to 52 C, and it's still rising(pretty much stable at 56 C now).

I played a game(Medieval II: Total War in high settings) for half an hour, and after I closed the game to see the temp, it was at around 83 C, but it was in the 90s during actual gameplay.

I don't think these temperatures are normal. I'm wondering now that maybe my GTS 250 is going down the same path as my old 220. What can I do to resolve this issue? Does it have anything to do with the HSF or thermal paste?

These are my specs:
OS: Windows 7 Home Premium 64-bit
Processor: Intel(R) Core(TM) 2 Quad CPU Q4800 @2.66GHz (4 CPUS) ~2.7GHz
Memory: 8GB RAM
DirectX: DirectX 11
Video Card: NVIDIA GeForce GTS 250

This is my PSU unit:

 

[precursoris]

The room temperature is about 23 C. It is not a hot room. The PC tower is on top of the table, right by the monitor, but is in a corner.

My GTS 250 is new. So should I re-seat both the GPU and the CPU? I've never heard of it being done on the GPU, but I'm not experienced. How do I re-seat the GPU? Do I add thermal paste just as I would do to the CPU?

 

[nforce4max]

It seams to me that you have an airflow issue perhaps you need to move the pc for better ventilation. Second adding fans ware there is proper room for one is a must. Third is there any fan near the card?

 

[precursoris]

It seams to me that you have an airflow issue perhaps you need to move the pc for better ventilation. Second adding fans ware there is proper room for one is a must. Third is there any fan near the card?

There is no fan by the card. Also, I don't have any extra fans other than the HSF. Which fan do you recommend from here:http://www.memoryexpress.com/Products/Computers(ME)/ComputerComponents(ME)/Cooling(ME)/Default.aspx

Will my PSU be able to handle an extra fan above everything else?

Also, I don't have a special case. I didn't build this computer, I bought it from a tech store.

 

[nforce4max]

It should most fans barely use any power, I even took one just for kicks and powered it using solar pv cells. Do you have a camera that you can take pics with?

 

[precursoris]

But which of these should I get: http://www.memoryexpress.com/Products/Computers(ME)/ComputerComponents(ME)/Cooling(ME)/Default.aspx

 

[precursoris]

Actually I have room for an 92mm case fan for the back. Also I have room for an internal (non-case) fan. What should I get from here: http://www.memoryexpress.com/Products/Computers(ME)/ComputerComponents(ME)/Cooling(ME)/Default.aspx