Sorry to hear that you're having problems....
But don't forget to actually TREAT your elbow/arm, don't just switch racket/strings and expect to never get TE again.
There's plenty of threads in the Health & Fitness section about TE/GE with treatment options, I'd suggest you read up on them.
Don't forget about arm flexibility and breaking up muscle spasms/knots/trigger points.
Babolat APD/RPM Blast 18G @ 53#.