Need to crisp up the edges of this image

[Joe 90]

Hey, I've never been able to get the attached logo to look crisp which really annoys me every time i load up one of our pages.
as you see on our nice new forum;
http://forum.shuwarriors.net/index.php?styleid=6

Trouble mainly being (other than I don't know what technique to use) that i've never had the image in vector form.
It first came to me as a jpg

anyway, if someone could give it some crisp edges, or tell me how (reference to something online would be great) then i'd be awfully happy

*okay, invalid file;