Integrate a payment gateway with a shopping cart plugin

Hi, need to integrate this payment gateway offered by this website: pagosonline.com, with a shopping cart plugin called Marketpress: http://premium.wpmudev.org/project/e-commerce/

This are the features needed for this project:

- Must work in wordpress multisite installs
- Must work in a per site basis
- Must work in single wordpress installs
- Must be translatable into spanish with poedit
- Must be a different plugin from marketplace
- Must include the option to change this settings in the admin dashboard:
- Encryption key
- User Id
- Currency
- Mode: (test or live)

Please set the best price you can offer, and set an specific time of delivery, this is actually urgent.

Willing to spend $100 to $200, and to get the project in 1 - 2 days.

I'm attaching the necessary files to do the project.

Thanks for your time.