Take it to an old computer bench tech. He may be able to fix it for $50. Elsewise you're looking at a $299 exchange price. Repairability is based on just how the slot was broken. Or live with one slot. You can install up to a 8 GB stick in that one slot.
RAM Type: PC3-10600 DDR3 Min. RAM Speed: 1333 MHz
Details: Supports 1333 MHz PC3-10600 DDR3 SO-DIMMs.
Standard RAM: 2 GB Maximum RAM: 16 GB*
Details: By default, 2 GB is installed as two 1 GB modules.
*Officially, this model supports 8 GB of RAM, but as first discovered by OWC, it actually is capable of supporting 16 GB of RAM using two 8 GB modules.
I have now repaired two of these with broken upper RAM slots by building (with plastic tooth picks) picket fence structures and super gluing them together and to the bar on top of the RAM slot so that it press down on the RAM stick. The first one has lasted a year now and the second for 6 months.