Power Steering Pump blew

[7TE]

I own a 1970 2+2, and my power steering pump recently blew. I see that XKs Unlimited has a rebuild kit for $12 which seems to be the right way to go. However, I am having a devil of a time simply removing the pump from its placement. I removed 2 bolts and the 3rd bolt (at bottom) cannot be removed because my ratchet wrench won't reach. There is also obstruction above the pump which may make removal from the bottom up impossible. Questions: (1) Should the pump be reomoved from underneath the car? (2) Is rebuilding the old pump with the new gaskets a fairly easy job, or should I buy a new one altogether? (3) I have not driven the car for fear that the empty steering pump reservior will kill the pump --- is that a correct assumption? Thanks in advance for your advice.