Cannot get my iCal to update and sync with my assistant.

I am US based and share my iCal with my assistant who lives in the UK. She makes the entries and they appear on my calendar. This has worked for over a year -- until last week.

The entries she is making are now not appearing on my iCal on my MacBook Pro.

They do appear on my iPhone and iPad.

Running Mac OS X 10.7.5

Last week at least 2 things happened.

I had to change my password in Outlook because I may have been hacked.

And I had a software update take place as they do periodically.

Cannot figure out what to do so any help will be appreciated.