OsCommerce Programmer - Must Be Very Experienced and Very Fast

Currently have v2.2 OsCommerce. I need a few functions added to my shopping cart and a few functions added to the admin. Here is a summary of the tasks:

Shopping Cart:
1) Integrate Authorize.net payment form into shopping cart.
2) Add an automated discount code to the order receipt.
3) Widen shopping cart by 1cm.
4) Edit some text.
5) Misc.

Admin:
1) Add shipping option to each product.
2) Add a sort order for each product.
3) Misc.

Must be completed within 1 week.
Only experienced OsCommerce programmer.

Thanks.