the door handles go for unreal money on ebay, usually about £70. However, having backed into a concrete post in my freelander commercial in a pitch black car park, I had the same problem.
I managed to fix mine fairly convincingly, even though it was in about a gazillion pieces. The key is to make sure you stop and pick up all the pieces at the time, then it can go back together without gaps. Forget the embarrasment, everyone's seen you do it anyway.
Take the inner door cover off the tailgate, four screw along the bottom edge, then pull hard from the bottom and the cover should pop off from the fasteners, but watch for any which fall out. Then, if you look top right, where the door handle fastens, you will see 3 nuts, which you should take off. The handle should then wiggle free enough to undo the plugs for the door release and number plate light. Once thats done, remove the handle for repair.
The plastic it is made of seems to be a bit funny after a few years and is quite difficult to stick properly. To make a good repair, you need a tube of super glue gel, and a tube of araldite rapid. Assemle all the bits, so you know how they are going to go together. Then stick them together using the super glue, one at a time working from the back of the broken bit to the front, so they all fit together. The super glue will go off super fast and hold all the bits together while you do the next stage.
Roughen the back of the affected area with sandpaper or emery cloth, to provide a key for the araldite.
Then mix up some of the araldite, not a lot, bout £2 coin sized, as it goes off bastard quick. Smear the araldite over the back of the crack, covering it completely and going over by about 15 to 20mm onto the good plastic.
The theory is the super glue goes of quick enough to suit sticking the bits together, but has little mechanical strength. Then the araldite provides the mechanical strength, but doesn't go off fast enough to do the sticking together bit.
Leave somewhere warm for a couple of hours then refit.
Did it to mine, glue cost about a fiver against £70 for a replacement.
Good Luck.