kernel - Remove 3.8.0-030800

I have a HP Pavilion dv3-2150 ep with 12.10 x64 ubuntu.
I don't know much about ubuntu, but with some patience and google, everything's possible...
Yesterday i had a problem after an (automatic) update, my atheros wlan card didn't work (i connect to the router, but haven't internet), so i google for some solutions... After some possible solutions, i saw someone recomend to install 3.8.0 (with issues, i was aware, from here : https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1097334).
I allready tried to remove 3.8.0 linux-image (saw here: Removing old kernel entries in Grub) but still continues there. For now i have updated to 3.5.0.26 (that solved wifi issue, but to enter ubuntu when i turn my pc on, i must keep shift key pressed, then choose 3.5.0.26 kernel. If i do not do that, ubuntu don't work. Another issue is that every time i turn ubuntu on, i must go to command line to turn wifi on (i can't see wifi before do that). Could you guys please help me with this 2 issues? Tanks...