I was in a similar situation to you, I got recommended by a friend to see london web, they gave me a hosted voip system, with three numbers and the ability to easly, divert call's from office to home/mobile, , plus many more tools and features, they can link phones into the systems, dont know if they can do yours, i would think so though. Also my voice messages get emailed to me for free, and i can call between phones for free no matter where i am, at home or away, as long as i have the phone,

there number is 02083494500 there on the web as well,

hope this helps