The best place for buying BIOS chips is
www.badflash.com
The customer support is terrific - if you are unsure as to what you need to order than just Email them with your board model, and revision, and Jack will straighten you out - they charge ~$25 a chip + shipping = it'll arrive in a day or two. Great website - I wish more people knew about it.
Although, I reccommend you buy a "BIOS Savior", so that if this happens again you won't need to fork out more money for another chip. You can get a BIOS Savior (You need model RD-1 PMC-4) from
www.frozencpu.com for a great price - or from
www.pcmods.com . Make sure you email them after ordering, so that they know to flash it for you - otherwise they will ship it to you unflashed (and useless to you, untill you get a replacement chip).
I'll bet that your chip is simply corrupted, and not physically destroyed. The BIOS Savior is not only a replacement BIOS chip for a small amount more, but is also a backup chip - you can re-flash your old, corrupted chip easily with it. I have one for my NF7-S, and although I haven't had any BIOS issues yet (unlike my old A7N8X...) I find the BIOS Savior to be useful as a safety blanket, and to use two different BIOS files for testing, and easy, flash free switching.
If you have any questions please PM me here on the forums - I would be glad to help.