After 1911 it gets more difficult as if searching in Ireland wasn't difficult enough, sometimes it easier before 1911. Most genealogy offices only keep records bmd's up to 1900.
Turn to the Irish telephone book for Westmeath and there
are 26 McManus in the Athlone area and 6 Jessops. I don't know the cost of phoning to Ireland (I'm in Canada) but
I always like to write anyway. Stamps are cheaper. You can write a letter introducing yourself with your known family tree on the back and have it copied 30 times and get some stamps. Addresses given as sufficient for mail delivery and a postal code (except for Dublin) is not required.
The biggest problem will be if she married and then women just disappear.
Another method now of contacting people is facebook, I don't use it but lots of people do and if not can find someone to do it for them. This can be very effective.
If you want to look for marriage & death registrations you will find these on www.familysearch.org