Change metric to imperial on 2006 Legacy monitor?

[Emgee]

Hi, new to the forum and it's a question I'm afraid! I did check the search function bit that didn't help... I've just bought a used 2006 Legacy 2.0 Tourer and all the fuel gauges on the monitor are in KPH. The satnav is in miles though and works fine (I actually think it's the most intuitive satnav I've ever used). 

Can I change the gauges from metric to imperial? If so then please tell me how!

Cheers, Mark