I think you will benefit more from a "SEO" search engine optimisation company than any "submit" services like that of inktomi paid inclusion, teoma, altavista etc.
Basically now that Yahoo feeds off the Google database there's probably about 75% of search engine traffic right their with Google/Yahoo searches, probably even more.
The other hits would be coming from MSN which reads off the Looksmart database followed by Inktomi, As for a field with Web hosting it is quite competitive so the Inktomi results will be a fair way "blogged" down in the MSN results.
2 UK based SEO companies off the top of my head who are ethical SEO companies i will list below, However i have no personal experiences with them. You get to know the long-lasting SEO's who have been in this business for a while.
1 Design 4 Life
You already have something good SEO wise going for you, I'm sure if you pick the right SEO company then your traffic could be alot better.
Hope this helps.