Yes, it is called overburning. The extra amount you can burn depends on the drive and the CD-R. You can check just how much in your case with Nero CD/DVD Speed: Extra menu -> Overburning Test ... Typically it is 2-4 minutes over the 80min mark.
Enable overburning in your CD mastering program.
You cannot, not on a regular 80 min CD-R. You can find 90min and 99min CD-Rs, but those are typically low quality. Most CD players have trouble reading past 90 min anyway, so it looks like you will have to go with two discs.