No, stop getting a VPS. I'm giving you this advice from the bottom of my heart and I don't want you to go through all the troubles and issues that I had while I was on VPS. I got my own VPS just a few weeks ago but it didn't do any good to me so I had no other choice but to go for a dedicated. VPS is STILL considered as shared virtual private hosting so it's not really a good idea to go for. I never ever had such big issues while I was on shared hosting until I've moved to VPS. I highly recommend you to get any of the dedicated plans by
Liquid Web. At least, that's where I got my dedicated a couple of days ago and I gotta say that I'm really impressed with the change so far. Your forum is definitely huge as it is already so you must get a dedicated one. The webmaster series will do just fine. ;]