GTS250 Overheat problem.

My Graphics card is
Galaxy Nvidia GTS250 512mb

As far as I can tell my Graphics card has ALWAYS averaged a temp of 80-85C (EVGA Precision v3.0.4), this is above 90% GPU usage, this is also at a forced fan duty cycle 100% when > 80C
"Idle" temperature is 70C, that's at around 25% GPU usage.

Of late I am inclined to believe it has degenerated.. the heatsink is absolutely dust free, as is the fan's interior, I used a vacuum cleaner on the fan and have washed out 3 pounds of dust from the heatsink twice since I bought it, yet the card's temperature continues to climb, eventually shutting down when it gets to around 97C(this within 20 minutes of playing a game). My cabinet is well aired, tho indeed I can watch its temperature climb 90+ slowly but surely even with my cabinet OPEN.

EDIT: Using Precision's warning I can alt tab at around 95C leading to immediate drop in temperature(to around 80C or less), and thereby avoid overheat XD. PS. GALAXY I HATE YOU.

I do live in India and the temperature is quite high I suppose. My card is not in warranty any more. The ONLY solution that DOES work is lowering my card's GPU speed to around 650Mhz (Default is 738Mhz), but I just feel like I'm cheating myself when I do this.

Will a liquid cooling system solve my problem?

Will upgrading my card's fan to a more powerful or better designed one help?

Will continued operation at these high temperatures damage my hardware?

The thermal paste I have used is not a new or expensive tube, but I am confident I have applied it well, I have a steel cabinet and even with the side open the entire lower section of my cabinet gets really hot, visible parts of the heatsink become EXTREMELY hot, inspite of this will using a better quality thermal paste help me?

Anything that might help?

Thanks <3