Google Map API pages upgraded from V2 to V3

General information for the business: We allow users to upload cycling routes in the UK
Description of requirements/functionality: We have a website, UK based that allows users to map routes and add details.

Cycle-Route.com/Cycle-Route-Planner.html

Only one function has noticeably stopped working - we had a box where you could enter your postcode and centre the map to it on the top right, that stopped working and upon further investigation it looks like it's because that area of the site was v2 of the Google map API so I would like someone to upgrade any coding calls that needed it and make the Centre Map to postcode work again.
Specific technologies required: Google Map API V2 & V3
Extra notes: I cannot give access to the live server, I can only email the php files through to be updated, I have a zip of all the php files from the folder which deal with the route planner.