We have just bought a website iPhone App and code is transfer possible

We have just bought a website iPhone App and code The previous owner built the App and has a developer account. What would be best in these circumstances. Start a new Developer profile and then add/ upload the App again or try and transfer the old developer account into our name.

The App is currently available and being downloaded and used but we do not have access. The seller is very helpful and cooperative. Just looking for possible ways to take things forward.

i guess this has happened before and is not new.

many thanks

p.s. sorry if I have used some of the wrong vocabulary I am new to many of the concepts and processes for developing Apps. iphone sdk, etc.