Yep, I agree, but about time, the scale you said seems to me that it should be way way way higher.
Maybe if that relates to the time needed to pull out the ´tech´ work you need to achieve the art, it still sounds a bit low.
But making full art as a creator requires the time with the references, research and a lot of try outs, unless you get a layout, like a publicity agency.
You can and should put up some method into it, deliver layouts, mockups, references, place holders, achedule and planned scoped work to your artist so that he knows what it is about, it gives confidence. Then it will be less about creating and more about executing, then it can be fast and cheap.
But seriously, if you don´t deploy anything at all, no artist is going to take the go, unless unexperienced chaps looking for a chance to portfolio, in which case, the stakes on getting it done is doubtless (but I like the option, to work with new people). Be aware of the daily price of art execution (not creation), at a somehow competent level, should be around 200-800 dollars freelance.
I agree you should also look into it, some styles are easier to pull by oneself, and many cases can fit your bill.
The photograph choice is great, you will have to do some clean up on photoshop later, but I like the idea.

Anyways, if you can advance your game idea, code and all, with place holders, the better the chance someone will pop up, since at that time things will pretty much be on scale as the code dictates.
When looking for something you don´t wanna do yourself and commercially, the more done on your part before you ask, the better.
I can lend a hand to you Mr. T should you need it for something to get the game and coding more advanced, like a layout/place holder to art.
Time is an issue on my end as I am the freelance artist I just described, I can´t promise anything, but I have good will.