High-Quality Logo Refinement Needed

I've got a few mock-ups of a logo design and I need a graphic designer to draw out a high-quality version of it. The final product should be a PNG file, suitable for use on my website, print materials, and social media. There is no need for multiple variations, just one polished version of the logo. Ideal candidates should have a strong portfolio in logo design and be able to deliver the final product in a timely manner.