New wild caught snake. Lots of questions.

[tstill14]

Okay, so I live in Oregon near Portland and I was out with some friends at a park when a really cool snake, a garter snake we all thought poped up in the forest right next to us and we caught it. It's about a foot or so maybe a few inches longer, and is slender. It also has a single solid orange stripe down the middle of its back, and is dark brown with black spots in a line to the left and right of the orange stripe on the sides of the snake. Also the bottom half of the snake is a lighter brown color then the top half. Im sure it would be hard to know what it is just from a discription so i attached a pic below. Any info would be great. thanks.

So my questions are,

Does any one know what kind of snake it is?

what do i feed it and how offten?

what kind of heat source does it need?

how big will it get?

basicly every thing to keep the little guy or girl happy and alive.