60 pound which I guess is still under $100 us seems scary to me when it comes to interfaces. The audio interface is the most important piece of gear you will purchase for computer based recording. Like all gear you get what you pay for.
The drivers are paramount. But most brand name top sellers will have W8 64 bit drivers.
What I recommend is making a list of the features that are important to you.
How many inputs you use at a time.
What type will you use? XLR, 1/4", RCA , SPDIF and MIDI.
How many out puts and what type connect to your monitors ?
Headphones and controls for balancing the input with the computer playback.
Do you need phantom power? and if so does the device run on only USB power or is there AC power option.
Is it built well? plastic of steel.
Do you want to use Guitar rig or real time EFX's?? then you'll need low latency.
Some interfaces also come with a basic version of recording Software. This can be a good value added bonus. Example the Roland interfaces come with X version Essentials. I think it's Presonus comes with Studio 1. Some have CubaseLE etc.
I don't think Sonar 7 was made for W7 or 8 and 64 bit so I wouldn't really expect great performance from it. I know some people do but personally I'd get a newer version.