modifying the signup button on Blogs MU theme

modifying the signup button on Blogs MU

I have changed the "Join Your community FREE" button with the membership plugin registration page (http://weightfan.com/)...I now have 2 button ( 1 small and 1 big)..
How do i correct this in the code? Btw,I'm not an advanced php coder.
Any guidance will be appreciated.
Cheers...