Upscale Logo to High-Res Transparent

I have only a low-resolution PNG of my logo (well under 500 × 500 px) and every time I drop it into a document it turns blurry. I need the artwork rebuilt in a much higher resolution with a perfectly transparent background so it stays crisp on both printed and digital materials... (Budget: £20 - £250 GBP, Jobs: Adobe Illustrator, Adobe Photoshop, Graphic Design, Illustrator, Image Processing, Logo Design, Photoshop, Vector Design)