sounds like the front seal of the gear is leaking. you can buy a reseal kit or complete rebuild kit, but if you arent familiar with rebuilding these or have very good mechanical aptitude i would not suggest doing it, bring it to a local mechanic to do or buy a reman'd unit.
another option that works very well if the leak isnt major is to try some lucas power steering stop leak, can get at walmart for $10 & it actually works. stopped a minor leak on my front seal & has been leak free for 5+ years until i get around to replacing the seals.