Another thing:
Here are the system requirements for Lr 4.3. Does your book qualify?
Mac OS
- Multicore Intel processor with 64-bit support
- Mac OS X v10.6.8, 10.7, or v10.8
- 2GB of RAM
- 1GB of available hard-disk space
- 1024x768 display
- DVD-ROM drive (if installing from DVD)
- Internet connection required for Internet-based services*