Be cautious of up-scaling raster (pixel) images as you can get lots of pixelation artifacts. You've probably noticed this by now. If your logo isn't too complex, you can use Inkscape (also free software similar to photoshop) to import the image, trace it to a colored object, and output a SVG image. It's more complicated than this basic summary and you'll often have lots of manual editing to do, but it's worth the effort if having a scale-able image is important to you.<br>