It's really going to depend on the artist. For a simple black and white comic page it could go anywhere from about $80 to $200+, color can add even more. Figuring out how much you're willing to spend and how flexible you're willing to be on a project will make a big difference.
Also not sure if you've worked with an artist previously, but one thing I'd say if I were to adapt the script you laid out is that you've got a lot of action/detail per page. I would say this would work better as four pages instead of two.
One thing that might help is if you tried making thumbnails/layouts yourself. Thumbnails can basically be stickfigures as it is, but it'll help you see how much room per page each of these panels would take up and would help direct any artist you want to work with.
If an artist is expected to draw multiple figures in action scenes with background elements, it may cost a fair amount to make sure that it's worth the artists time. Depending on the complexity of the page, it can take anywhere form 4-12+ hours. Important things to keep in mind.
I hope this helps and good luck! Even though the results might not be what you want, I recommend trying to draw it out yourself if you haven't already. It'll really give you a good idea of what to expect if you do decide to work with someone and really will help you communicate better what you're trying to achieve.