For signal strength/channel strength:
Android - WiFi Analyzer
*nix - LinSSID
Windows - Xirrus WiFi Inspector
No preference/experience on apps for OSX or iOS.
Aye, true.. Your BIOS is very old - you could try upping it to A14.
Also, if you can borrow a USB wifi card, you can see if it is your built-in wifi card.
Edit.. How about LinSSID