Reckon it's best to wait for a provisional job offer before forking out for the TR. Alot of airlines seem to offer this kind of deal so I reckon get through the interview first then focus on the TR with a course approved by the airline and the prospect of going straight into the job on completion of the course.
Thats my humble opinion anyway. Thats the way it worked for me and got a few hundred hours on the 737 NG.
Alot of hard work (hate to sound like a loreal advert) but it's worth it.