Logo Change res

Hi I have a? very simple logo and need it removed from the background so it is just a black dog and be made in to higher res as the res is not high enough for me to have printed on to shirts etc ## Deliverables Hi, I am not techy at all and having problems trying to put my logo on to a polo shirt as the resolution is not good enough and I dont have photo shop? I also dont want the white box around the logo, just the logo of the black dog itself in high res. And in a format that I can change the size should I want. Many thanks