CRE Loaded Existing Order Payment Option

We have an existing CRE 6.2 web site that has several modifications already - we are looking for an individual to complete another such modification. Currently, the only way for our clients to make a payment is when they place the order. Due to the type of business we are in (printing of custom business cards, postcards, etc), we often create a special order for our clients in the admin panel, and then we have to call them for payment information. We would like to add the ability for our clients to make payments on an existing order that is created for them. This is how the modification would need to work: 1. We would create the order for the client, or the client could place an order without making payment (we have an option for that already). 2. When the order status is changed to "Waiting for Payment", the user could view their order in the order history and click a button to make a payment. This payment button or link would only appear when the status is set to "Waiting for Payment". 3. Upon clicking the link / button, the user would then see a screen (within the site, not a pop-up) that would give them the option to pay by Credit Card. They would use the secure payment module (or a copy of the module) to complete their payment. Once payment has been received they will see a message letting them know that their payment has been received. Keep in mind that if a card is rejected or declined, we need to post the appropriate message. Also, the amount due for the order should be displayed in the total amount due for the payment module. 4. Once the payment has been approved by Credit Card, the job status must change to "Waiting for Files". This will give the client the ability to upload their files to us (the waiting for files and upload ability is already operating on our site, you just need to change the status after a successful transaction). We have several other additions and jobs that we want to make to our site and are looking for a programmer that we can use from time to time. We want someone that will have a good working knowledge of our site and be able to implement these concepts efficiently. Please respond with ALL questions prior to bidding. We would also appreciate a well thought out description of how you think this will work.