Vextractor

Vextractor offers you easy conversion of raster images to vector formats by creating internal and external lines.

The application can be used to convert tables, maps, charts, logos and other similar images to vector format. The program has a useful function to recognize squares, circles and orthogonal lines as well as it can handle smoothing of curved lines, noise filtering, etc.
Supported input formats include BMP, GIF, TIFF, JPEG, PCX and TGA.

So this is the fastest method to convert a logo that you then need to enlarge without losing quality.