Plugin for Mass Product Categories adding?

I currently run an e-commerce website and have just uploaded 1000 new products from my wholesaler with a csv file. Unfortunately the csv didn’t contain the same categories as on my site for the products so it means I can’t use it to add the categories because I obviously want to put each product in the specific categories listed on my site. It means I am going to have to go through each product by hand and assign the correct category which is going to be very time consuming. Is there a plugin or a hack I can use to speed this process up?