Need a Very Good PHP Developer for an Important Task right now. - repost

Need some urgent help to fix a few things on our website. This should take a few hrs for the right person. The coupon feature on our website does not properly. We need the coupon code entered applicable to only the costs of the item and shipping costs or Tax cost should not be included. Example: If the cost of the item is $35 and the coupon code is worth $45 then the cart will have a negative balance of -$10. If the customer wants to checkout then he will have a -$10 in his cart and when he is about to checkout then he will select a shipping method and if shipping cost is $5 then that $5 must not be included in the coupon redemption. The coupon must be applicable only to the cost of the items and customer must still pay the $5 for shipping. I need an import option in the admin where we can import any number of coupon codes to the admin from an excel sheet. The coupon codes should be valid only for one time use. If the customer redeems $35 from the $45 then he must redeem the $10 left at the same time or loose the $10. There are a few other tasks that are needed which I will explain as we get started. Must have good experience and good feedback.