Bleuze –
If you are getting 450 uniques a day from only being online since February this is great! Most people only aquire that after a few years. Are you sure this is uniques and not page views?
The reason I ask is, if these are actually “uniques” and you aren’t getting many signups, then I would start looking at how long they stay once they get to your site. Maybe you need to do something to keep them there once they get there, know what I mean? Try making some changes to your home page – enticing titles or graphics to perk their interest. Maybe they are not finding what they came there for? Try some experiments.