My client deleted her user that was the vendor. Is there any way to fix this besides using a full site restore? Can I create another vendor or anything?
Using Joomla 3.4.5 and VirtueMart 3.0.12
Try adding a vendor record each in virtuemart_vendors, virtuemart_vendors_en_gb and virtuemart_vendor_users tables. You can find vendor id in products table.
You can enter a new user in the BE, make sure they have address etc set and are a shopper. Then make them Admin/superadmin as required and in Tools & MIgration/Migration at the bottom of the page is a config to set the Store Owner by their userid.
http://docs.virtuemart.net/manual/tools-menu/70-tools-migration.html