Hi, my app Simple Purchase Orders can definitely meet your shop's needs. It allows you to set up suppliers and import products and set cost prices. You can then automatically generate purchase orders from orders your customers make and it will import all of the items they order and their address and email it to your supplier. It can also handle splitting orders into multiple POs where the items have different suppliers. This should help you reduce time spent fulfilling orders and eliminate mistakes.
Please check it out and let me know if you have any questions