I dont know about windows 7 but if you are looking for Windows Server 2012 VPS I would recommend you try out this: http://www.ajkservers.co.uk/windows-budget-vps-servers.php
Most hosts do not offer Windows 7 or XP due to the Microsoft SPLA, as well as the licensing rights associated with it. Unfortunately, your best bet would be to get your own license and install your own .ISO on the VPS. Most providers would be happy to do that for you. Unfortunately, the cost of the license isn't going to be cheap, unless you have an unused license laying around. Not sure there is going to be any alternative.