Prep/Condition your leather with a Over-the-counter leather cleaner/conditioner.
Just a short trip to your local advance auto and you got a good solution to your problem (walmart is highly recommended as I know that they have both Mothers products and it's usually a lil cheaper there).
1.) Mothers VLR complete interior cleaner/detailer (vynil, leather, rubber).
2.) Mothers Leather cleaner/conditioner (leather care).
Try that for now and then move up to the professional mail order stuff. Anything from Detailers Domain is Great. Someone did a article about a year ago on here reviewing the Swissvax leather care treatment.
1988 325i sedan (Cirrus Blue Metallic, Silver Grey Leather)
2011 128i convertible (Blue Water Metallic, Grey Leather)
2013 320i sedan Sapphire Black Metallic, Black/Black