The yeast has died, and the hops will be pretty stale. The malt extract will be OK. If you have liquid malt extract, make sure to heat it up in a pan of water before you use it to ensure it will flow out of the can easily.
Buy some yeast (it's cheap - $3-5) and make sure to get the exact kind, or ask for a substitute at a homebrew shop. The yeast has a tremendous impact on the taste and character of the beer. If you've ever had a hefeweizen before, that banana smell and taste is entirely from the yeast. If you want to try the yeast out, you can proof it before you brew- heat up some malt extract on water to about 90-100 degrees, pitch in the yeast, and wait 5 minutes. If it bubbles, it's alive. If nothing happens, it's dead. This is the same process you use with bread yeast when you want to see if it is still alive.
Hops are added in two (sometimes more) steps, an early bittering step and a late aroma step. You can use stale hops for bittering, but I would buy fresh hops for the aroma step, if your recipe uses it.
I have oversimplified the process, but this advice will get you headed in the right direction. Good luck! Homebrewing is a lot of fun with a great community.