Editing "grey" wrap border (sides only)

[eduki]

Ok, so on the my site bestfrozendrinkmix.com i am using the corporate theme. it comes originally with a grey border around the site/homepage which consists of top.gif, bottom.gif, and wrap.gif. I have replaced the top and bottom with custom images i pulled from http://www.margaritaville.com/; however the two side borders on http://www.margaritaville.com/ are two separate images, rather than just 1 that comes stock on the corporate theme (wrap.gif).

So what i would like to do is replicate margaritaville.com and upload two side borders which i have on my comp. (left.gif and right.gif below) however i have to overwrite wrap.gif... i am not sure how to upload them separately...

http://www.margaritaville.com/templates ... R_left.gif
http://www.margaritaville.com/templates ... _right.gif

I need to take these two images above and overwrite this image below:
http://bestfrozendrinkmix.com/wp-conten ... s/wrap.gif

Any insight would help...

Thank you.

could you provide some insight?