Learn…. Learn…. Learn…..Convert the file to gray scale and manually trace in Corel Draw. Open up the "Object Manager" and create a new layer. Draw over your logo then delete the underlying logo. Time spent learning Corel will be invaluable in the future as you will not have to pay hefty out-source charges for vectorising graphics. Trace tools are good if you work on "that will do". If quality is one of your selling points then you got to learn…..plus you can add graphic editing fees to your costs.
For engraving purposes I would manually trace that logo in under 30 mins (outlines only) and charge the customer £15 set up fee and retain the graphic on file. (It doubles if they want to have a copy of the vector file).
In addition, by creating your own vector files you can build up the graphic in a logical manner (from the cutter/plotters perspective) and speed up the output process. When automatically traced plotter output can be random, producing excessive tool lift operations and extreme movement across the X & Y axis’s
Cheers