Half shaft inner can leaking- DIY somewhere?

[dbn1066]

My (left inner can) half-shaft is leaking pretty good. I've been searching for a diy guide with no luck (maybe its just my poor search skills). How long can this go before really bad stuff happens? Never dealt with these before and I could use some help. Do I replace the boot or can w/o doing the whole half shaft? I'm on a really tight budget at present. Any help is appreciated...
Dan