ok so where would i apply the patch for album art in my rockbox file or in my music files??
Neither.
Many people, when they hear the word "patch" think of the warez/cracks scene where
binary files are patched (modified) to change the binary file's behavior.
With a project like Rockbox, the goal is every so slightly different.
A binary patch is near worthless because it doesn't update the underlying source code, therefore it would have to be reapplied (if not recreated) every time a new build is created. If you'll notice the front page or "current build" page, new build come many times a day.
What my long-winded intro is trying to get at is that fact that the AlbumArt patch is a
source code patch. It is a cute little text file which you would apply to the source code, changing some lines while inserting others. Because it is a source code (not binary file) patch you will need to download (or create) a "build environment" - a set of tools to download, manage, and compile the Rockbox source code.
There are three different Rockbox supported build environments available from this website (cygwin, VMware, and coLinux), and they are well documented in the wiki
http://www.rockbox.org/twiki/bin/view/Main/DocsIndex#For_Developers.