Recently did that repair. It's quick and easy if you're decent with a
soldering pencil.
I bought the replacement battery from Erie Aviation in Pennsylvania.
$15.40 plus shipping.
Tel +1 814 838-8934. (Eastern Time)
www.erieaviation.com
.... for whom I am not a representative, employee, family member, etc.

Other more familiar distributors
(this space left blank so as not to anger anti-commercial-use people)
may carry this battery, but you won't find one at your local Radio
Shack Aviation.
Jim