I use a mix of forum ads, paid ads and adwords. The best form of advertising is without a doubt word of mouth though. To get this you must offer exceptional services though.
I have a couple of suggestions that might help you though.
1. Take that "Grand Opening" out of your signature. When people see that you are brand new they are a lot less likely to trust your services and give you a shot.
2. On your website, at the very bottom there is a lot of empty space. That needs to be fixed, filled up or removed.
3. On your website, in the header you have slider images setup but only one image in the slider. If you're not going to use the slider, remove it. You also must finish the one slider image you have now and fill it in with information about your most popular or most affordable packages.
4. The links in your header go straight to your WHMCS order pages. You MUST remove that and build some pages that give the visitor information about your packages before they will even think about buying from you! The way you have it setup now you're basically saying "Here it is, buy it", which obviously isn't working!
5. Your "About" page gives a lot of information about the datacenter that your server is hosted at but, it says very little about you! You need to give the user information about your company, not another company!
Anyway, if you do this I can almost guarantee you that you will start getting new clients!
Good luck!