Use Adobe Photoshop with the background set to transparent to create your .gif file. MS Paint is very limited in some of their features. I am not familiar with the starter edition of Photoshop, but if transparent .gif files aren't an option, check out downloading a free 30 day trial of the new Photoshop to make your file. Just ensure you make all your changes, cause you cant download it again without buying! : )
Adobe - Creative Suite 3 trials
Good Luck!