Editing a webpage in webview

I am new to iOS and Mac programming but old to .net so have some knowledge. I am on 10.8.2 using Xcode 4.5.2 on my lil MacBook Pro.

I am trying to replicate a program I created in .net for christmas shopping for the Mrs.

Basically its an internet browser that removes prices from webpages it browses. It searches the webpage for the £ sign, then . and then adds two. Once a price is found like this it removes it.

I already have a browser built with the webkit using the webview to display. How can I grab the webpage data and do this type of manipulation?