I didn't think your graphics were too bad. Even so, I can understand you wanting to make them better. Perhaps try somewhere like https://www.deviantart.com/. This is supposedly the biggest artist web site on the planet with over 26 million registered users. Some of the artwork there is absolutely fantastic and they do have pixel artists. Try Projects in the forums, where people ask for and offer their services, sometimes for free. You'll need to have a pretty good description of your requirements and allow them plenty of time to do the artwork. Good luck.