Help changing Chainring

[proflex3k]

Hey folks, Im a total Newbie when it comes to working on my bike - I have a Proflex 3000 I got from a friend for $100

I noticed the outer chain ring is toasted, all chipped teeth so I wanted to replace it.  Went to the local bike shop and paid $39 for a new outer chain ring. I opted to go for this vs a Rock Ring since I ride some roads and want to get up to top speed.

Anyway, here is my issue:  I want to remove the crankset or at least get to the outer chain ring so i can replace it.  I took off all the hex nuts and have everything exposed but cannot get the crankset apart to remove the arm holding on the outer ring.  I separated the other 2 rings from the outer ring, but am stuck at this point...Do I need a special tool or do I just need to bang one side out? 

Thanks for any help you can provide, I'd rather save some $$$$ and try this myself

Full size pics are all here: http://eric.myhomeserver.com:88/
Or I'll try and plop them in below

[Old Proflexer]

you need a basic crank puller - available from most shops for $8.00 - $15.00

OP

http://search.performancebike.com/search?p=Q&ts=custom&w=crank+puller

[orange]

I thought these were the sort of cranks you couldn't replace the outer ring?

[proflex3k]

Thanks for the reply, I'll stop by my local bike shop and grab this extractor.  If they have questions about what I need I'll show them the pics

and...It better come off, they sold me a replacement and it appears they can be exchanged/replaced

Thanks again folks!

[RhinoDave]

http://parktool.com/repair/readhowto.asp?id=103

http://parktool.com/repair/readhowto.asp?id=121

These instructions should help you out. Make sure you get the crankarm extractor for square taper bottom brackets and not the one for isis or octalink bottom brackets.

[proflex3k]

Thanks for those that helped, my local store had the crank puller for $15 or so and got that off no problem, I appreciate all the help!