Can I replace the ATI Radeon HD 6370 card on my laptop?

I have an HP pavilion dv7 with a Radeon HD 6370 video card that has been intermittently crashing, but now the problem is worsening. I have scanned the various troubleshooting recommendations and have determined, to the best of my ability, that:

1. The card crashes when the computer is cold or hot, but more frequently when the computer has been on for a few hours.

2. Windows researched the cause of a crash a while back and informed me that the error was caused by the ATI card.

3. I am using the most up-to-date driver.

4. My spouse is an electrical/computer engineer and is going to replace the card if I can purchase another one. To that end, I have these questions:

+ Is the card a standalone or is it soldered onto the motherboard?

+ Is there another card that might be more reliable that I can purchase instead?

+ Where can I purchase a replacement card?

Thank you.