Thoughts on replacing the power steering in an old Camry?

I drive a 1999 Camry 4 cylinder with 245,000 miles. I have owned it for a few years, bought it with 185,000 miles and use it for a job I do on the side that requires a lot of driving. It has been very reliable aside from a power steering leak that I had been quoted around $750 or so to replace. I have been topping off the power steering fluid every week or so when it would run low and it's got me by, until today when I attempted to drive the car and the steering was super tight and barely moveable.

The resivoir was completely empty which I found strange since I had topped it off not too long ago and the leak wasn't that severe. I topped it off, drove it around the block and the steering barely improved. When I checked the reservoir it was completely empty and I could hear a faint hissing sound, possibly coming from a hose but not sure.

Would I be crazy to just go ahead and replace it? I don't remember if they told me it was the pump or what, I know a decent amount about cars but not much about power steering systems. Car runs fine otherwise and is also not my primary vehicle but I do need it for this job. Thoughts?