OK! now if you have established that you are losing oil, if I would be you I will find out the cause of oil leak in the pump. Instead of going straight for the pump replacement or oil seals replacement because if the problem is somewhere else, this leak will re-emerge,
1) Have you, on a dark night, missed out on a speed (read back) breaker and took off and landed back heavily?
2) Did you touch bottom heavily over a speed breaker, big piece of rock, gutter lid etc etc.
3) When was the last time you had your steering rack lubricated/greased?
In case of former two, I reckon you may have a bent steering rack which may be causing a pressure surge or it could be just a relief valve going off (one off case) or damaged seals and in case of last, gears may have become jammed and your pump is struggling to cope with the force required to turn the wheel.
You can see the floor, where you park your car for hydraulic oil stains to find out.
So I think you should have complete check up before going for any pump or seals replacement.
Cheers,
Kaleem