I'm not trying to be a jerk or stick up for the dealer or BMW here but this is what i think . The dealer may seem like they don't care but there is nothing they can do for you , the vehicle has 135,000 miles on it , your warranty ran up at 100,000 witch is twice the 50,000 mile factory warranty . Yes is was an original manufacturers part that has failed , but they did give a 4 year 50,000 mile warranty plus you also had the 100,000 cpo warranty . I cant say that there is any manufacture that would give you any help at this point . They are not being mean too you , hate you or don't care but the fact of the matter is the warranty is out by 35 % .
I would recommend that you search for a used motor . Try to look on ebay and do a google search .Check with www.bmrparts.com .I would have the Dealer do it for you though .
Thanks and I truly am sorry for your bad luck .
BMW Technician
12 YEAR MASTER TECH