Using your 2801 to set up a second subnet is doable. How you do it depends on the capabilities of your Virgin router. Will the Virgin allow you to set up static routes or maybe even RIP? If not you may have to set up NAT on the 2801. You'll also need...
If it's only the EVEN ports failing and only the even, then I suspect that maybe they mislabeled the color code for the even numbered ports or the person doing the punching mixed using 568A and 568B.
