2003 Chevy Impala 2003 Impala stering & water pump prob

If your water pump is leaking, replace it asap. A refurbished one will cost you around $15 at an autopart store; a little more for a new one. If you have it done at a shop, it's gonna be around one hour of labor + parts, so probably around $200-250 more or less depending on where you go.
As far as your steering problem, make sure you're not running low on power steering fluid, and check for leaks if you are. If level is alright check your power steering pump and pulley.