nudge

Hi
need help, me sis owns a limited auto wrx saloon, of which 500 were made, problem is she is loosing drive in 2nd-3rd change up and 3rd-4th, running in permanant 1st and 2nd is fine.
she was told her car is fitted with 2 torque converters which i find hard to believe, two pumps maybe, but never heard of two converters.
what do you reckon.
had one quote of 1700 quid to recon,
second will a wagon auto box fit as an exchange unit......?

cheers in advance