Whille I shop at Gelson's all of the time, I am not a fan of their Jewish Holiday foods including the gefilte fish and matzoh balls with chicken soup. My suggestion is Katella Deli. They make pretty good everything.
It's never too late to learn how to make it :). The recipe I have, and use, has been passed down through many generations. My children will pass it on. If not, friends purchase it at Nate 'n Al's and it's delicious.
Gelson's markets carry it closer to Passover in their fresh deli. It's a little on the sweet side but my kids love it. They also carry a very good full Passover menu. They will start taking orders this year on April 4th. http://www.gelsons.com/shop/SD/simply...
I use Ungars brand which I get at Albertsons. It is a frozen load. They have sweetened and unsweetened. We get the unsweetened and add carrots, onions and a touch of sugar. I sure do miss the real homemade mom used to make though.