PHP/Ajax/Javascript Development

I have produced an eCommerce site using WP-Ecommerce which requires a 'tank picker' and 'tank size calculator' developing.

These will rely on users selecting options and entering data into a form which will then show results according to a client supplied MS Excel formula.

Visuals are attached to this job post, ideally I'd like the form to be live so calculations/validation can be done on the fly.

Interactive roll-overs for the 'what's this?' links will display overlay pop-ups (the same as on PPH).

The tank size calculator should communicate with the tank picker so when the size is calculated, it automatically populates the relevant field on the tank picker.

This all needs to work by entering the relevant code into the HTML editor of a page with the WP framework - maybe by using shortcodes??? I'll leave this to you to decide the best solution!

This is a short deadline I'm afraid - it needs to be completed by Oct 4th.

Please provide a fixed quote for the work and relevant examples of similar previous development jobs you have done.