I sympathise with Tony. I have a similar issue myself, only Im dealing with several million of hits per week and thousands of individual users per day. The main site is still by far, way busier than the forums and the adsl checker alone has a huge database accessed by several users per minute. The forum isnt as busy but its still accessed by anything from 40-100+ people each and every second.
Ive gone down the well worn path of shared hosting, cloud hosting, advanced business hosting, bespoke hosting and dedicated. No webhost will touch me unless I go dedicated - its been like that for years - and its my choice to use UK webhosting because I need managed support to take care of crucial server software updates. For decent dedicated hosting with decent support in the UK then a starting price of > £100+ VAT pm sounds about right to me. US hosting is way cheaper, but I could not do with the additional latency, nor would I be just a (0800 24/7) phone call away from support. I pay annually and like most owners behind such community sites we've all put our hands deep into our own pockets to sustain a site. European hosting is perhaps a good midground, but I think if you are serving a UK community then you need UK or European hosting, you dont want to be crunching numbers on a sever several thousand miles away from your audience.
That said, MDWS is database driven so aside from the database then storage isnt going to be a big deal as theres no large files and each display is simply number crunching from the database so CPU is going to be the main requirement. Based on the fact of 60 active users then whatever the mechanics it doesnt justify nor is it ever going to be able to generate enough income to cover dedicated hosting. Based on the number of users and comparable to number of users of this forum which is also database driven.. then yes my forum alone (not counting the main site & wiki) would cope very easily on VDS and tbh it would even cope on cloud hosting/ high spec shared hosting with a reputable host.