Redesign of existing business card logo and text

So I had a free design done by a company that I then bought cards from. I was happy with the service and the finished product but now I'm looking at getting printed work wear done, I've now learned that the company do not sell the artwork!

This is a shame as I would have gladly paid for the their time and the art work file!

What I'm after is a redesign of the existing card/design work so it has just enough changes to legally be my property.
Again, I would have gladly paid the original company for this art work but as I can't I have no other option.

The logo is the main area that I'd like re worked and I have an idea for a slight change to the font/text design

Thanks for looking

Chas