With home plug you'd be lucky to get that. You'd be much better getting the old drill out and drilling two holes in the wall. You can also get ac wireless to Ethernet bridges but due to the walls etc the drop off would mean you're not getting the full benefit of the virgin connection.
Since the superhub is unreliable and works much better in modem mode you'd still be better buying another router running a cable upstairs from the the superhub into a the router. Or if want wireless downstairs run the hub into a router and then another cable upstairs to your office.

I agree that CAT5/6 is better than powerline, but AC repeaters are no solution (unless you live in a house of cardboard), since your theoretical speed is limited to 150Mbit/s.
The powerline AV2 (or 600) standard is pretty good AND backward compatible: http://www.tp-link.com/en/products/details/?categoryid=3140&model=TL-PA6010KIT

Stay clear of the 'gigabit' ones, that chipset is dying out because of reliability issues.