the products you will need to accomplish are:
Digital File Pro (for attaching the logo)
When the user first submits the order, use the eCart Store Order Summary and Store Order Details behaviors to store information about the order in the database.
The admin can then log into the admin section to update the order information, the admin section will be created using DataAssist. use SecurityAssist to add login functionality.
Use Universal Email to send an email to the customer containing a link to the order history page. You can then add eCart checkout to the order details page so the customer can accept the order and have it processed through the gateway.
There are a number of tutorials on the eCart, DataAssist and Security Assist support pages to help with putting these pieces together.
I would estimate the skill level for putting this together at around 7 on a scale of 1 - 10.