You may want to investigate the Leatherique line of cleaner/conditioner, and dye. You can clean out years of nasty dirtiness that is so into the seats that you barely see it; then condition the leather to re-soften it and keep it from drying out and getting brittle (leads to cracking). You can also get a dye to restore the seat color and make that off-panel blend in.
Link:
http://www.leatherique.com/do_it_your_self_instruction/
Stuff is also available thru autopia or autogeek, if you are getting other detailing supplies as well.
For the ripped seam, it looks like you could get it re-sewn once the seat cover taken off. For any rip in leather that is not on the seam, you can use contact cement to glue a patch of leather to the back side of the rip as reinforcement, then Leatherique makes a crack filler material that you would use to fill it prior to re-dying.
Hope that helps. There is a lot of good leather care info and how-to's on the Leatherique site that will give you a lot of knowledge about how to care for and fix leather upholstery. And no, I have no stake in the company
