Fix and error and install new modules on Oscommerce webstore

Looking for a SKILLED programmer to quickly fix a bug on existing webstore and install a couple new modules. Website is based on Oscommerce. It's live and working fine. However,

1. There is an issue with the "Points and Rewards module (POINTS AND REWARDS MODULE V2.1rc2a_1)" on checkout_confirmation.php page. Points are not actually deducted. They are displayed with a "-" but not deducted from the total. So the total remains unchanged. Other than that the module work great. It used to work fine a while ago, but then something happened. Can't figure out what's wrong: everything seems fine. So you will have to find the bug and fix it.

2. The second task, and probably the most difficult task here, is to install and set up a new module: "One page checkout" from http://addons.oscommerce.com/info/6646. You will not only have to install it but will also match design of the module to the webstore design so it looks nice. Also, make sure all other modules integrated in standard 4-step checkout are included and work properly: "Free Gift", "Discount Coupons", "Point and Rewards". The last one may require some custom coding. It means you need good php skills and know what to do.

3. We would also like to find and install a "Shipping estimator" module on the "shopping cart" page. Example is here: http://www.onlybestrated.com. We use several shipping modules "Canadapost", "E-shipper", "Free shipping". Make sure they are all quoted.
This module is a part of "Eshipper" package http://addons.oscommerce.com/info/5711. It might be also be done as a part of existing checkout_shipping.php page, but is activated when the user clicks on "Estimate shipping cost" button.

4. We need a little improvement on checkout_shipping.php page. We use "Eshipper" shipping module, and it takes 10-15 seconds for it to retrieve quotes from the server (sometimes even more). When customers see the blank page for a while, many of them think the site is broken and leave. We lost many potential customers because of this. So since it's impossible to accelerate the module to retrieve the quotes we want to display the message "Please wait... Retrieving shipping quotes. It way take up to 30 second... " (or something) while quotes are being retrieved from the server. It should work this way:
- Display the message in the middle (or top) of the screen so it's easy to see
- Launch shipping modules to retrieve the quotes
- When quotes are retrieved erase the message and return to regular checkout process.
Please also integrate this part into "shipping estimator" module in the task #3 above.

These are four major tasks at this point. We would like to make more improvements after this is finished, so if you do what's required quickly and professionally we may give you some more work. We also need someone who would work with our website in future when we need upgrades. So consider it as the potentially long term cooperation.

In order to complete this project you MUST have good knowledge of Oscommerce as a developer and you MUST have strong php programming skills. Please do not bid if you are not sure what to do or have poor skills.

Please provide samples of your previous work if you have anything to show.

Thank you