Best way to update an outdated blockchain
You probably want to simply update your client to the latest version (0.10.1 was just published) and just run it. As of 0.10 it will download the missing months much faster. (As well as many wallet improvements.)

Forget about the bootstrap file, just cancel the download. It's three months old, so you would still end up with the same problem.

Also: you're probably better off regularly running the bitcoin client (maybe a scheduled task, once a week?) instead of letting it get behind 8 months. You might want to add the -listen=0 option, that way you won't have others connect to you and download blocks from you (saving you some bandwidth).

If it's really too heavy for you, you might consider a different wallet as Pieter mentioned.