Craig, from the sounds of it you want a host who will improve the speed of your forum and help get it on the map so more users are coming to it.
There are several qualified hosts on this forum(just do some searching), but to increase your user base your going to have to do some marketing on your own. There isn't really a magical host who will bring thousands of people to your board. I'd suggest running a contest with some good prizes, this really gives an incentive for people to start posting more.
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