If you are in the UK you might like to listen to the last half an hour of Bob Harris' show, where he puts together a compilation of songs from the McGarrigle/Wainwrights as a tribute to Kate.
I didn't put it here, but the last link reminds me of their being a nice new version of Martha's 'Bleeding All Over You' available as part of the Transatlantic Sessions, Volume 4, which was fairly recently aired on BBC Four. Hopefully the following link will take you to the Amazon Search page- where you will see the DVD (Which has the complete series- Martha sung more than the one song) as well as the CD - on which 'Bleeding All Over You' is on. I have not yet bought this, but I think it would be well worth it as I loved the episodes I saw. Oh and I used the Amazon link as it was easiest, but please try there and elsewhere if you want to buy it!