Sca,
Your CastSpellWindow is missing the new Spell Name Label, although you do have the slot ok. Make sure you use the EQType 133 for that spell name.
As for your BuffWindow, the 15-19 ones... the locations of them, Im sure, are not where you want them. And, you are missing the labels for those as well. As stated above, you might want to consider using the Labels for these for all 20 using #'s 500 - 519.
As for the graphics used from the spellbook window, that I am sure you can work around with to have everything line up all pretty
What I would do is make another tga file and draw your new buffslots in there, and make new references (uianimation, staticanimation) in your buffwindow xml file to load the new graphic additions.