Ok, it is possible that you could get more from your connection.

With that Line Attenuation you should be able to get around 9-10mb (see the tool on this site), where you are currently getting just shy of 6.7mb. However your Noise Margin doesn't have a great deal of room for improvement. This could be due to interference from internal wiring or something outside of your control (at this stage).

Could you plug the router into the Test socket, with just the short grey ADSL lead and a microfilter please? Then take the stats and post them up so we can see what is happening.

If you don't have the split faceplate described in the link above, please let us know.

The 2nd issue is WiFi strength. Basically the computer upstairs is struggling with anything fast. I would seriously consider connecting your old Virgin router using a pair of HomePlugs and locating it nearer to the computer upstairs.

If you were to use the method described in the thread below, then the Sky router would remain in control of your network, and the Virgin router would add an additional WiFi access point.

How to connect two Routers together

A pair of HomePlugs would set you back about 35.