with only 15 users online, yes that is bad. I suggest you migrate to another host with a vps or dedicated if you can. There is not really much more you can do to tweak the server if you have shared hosting.

Actually not really that bad, are you sure the issue not just with your connection i.e. have you gotten someone else to check it from a different isp?

no forum script is small enough for godaddy. I wouldn't recommend a dedi for a small board. He can use a shared box for that small (depending on the specs of the shared server and the server population). sometimes 20 Users online simultaneously and server loads rarely exceed 1.00. Good thing my host has the goody paid server at the back of the store because my host also offers free hosting so there's not much people renting the paid server and I think you just gotta find a host that doesn't oversell and someone you can talk to openly.

GoDaddy isn't the way to go especially if you're going to have to run DB Dependent scripts.

It might not necessarily be your problem. Seeing that you're on shared hosting, it could be another site hosted on the server lagging you down. Try checking with your host too.