Have you taken a goood look at your new bushing set to make sure it has outside metal rings?
Some of the sets tell you to leave the original outer metal inserts in the arm, clean it out and the new bushing fits into it.
Make sure you've read all of your instructions because if you push it out or damage it the new bushing may not work and then you have to go buy OEM rubber bushings to start over.
JayArr
If the outer metal ring does need to come out then use a tool like this:
http://www.amazon.com/Astro-Pneumatic-7 ... B00061SGZO
or this:
http://www.automotivetoolsonline.com/AP ... 14387.html