Have you talked to your BMW dealer yet to see what your options are?
I have a Route 66 extended warranty on my 2008 XiT only available through Credit Unions. Bought it before factory warranty ran out. Don't know if/how they cover older cars...
2008 E61/Monaco Blue/Natural Brown/Premium/Sport/Logic 7/Sirius/Escort 9500ci, Conti DWS. Build Date 1/08. HPFP replaced 6/10 and 4/11 Fuel Injectors replaced 3/11. Battery replaced 5/11 (warranty), sunroof seal replaced 10/11 free under SIB 540409. Pads and rotors replaced 11/11 under maintenance. Carbon buidlup on valves cleaned under maintenance 11/11. 59K miles. Original owner. BMWCCA Member. Route 66 Easy Street Warranty.