carol2004
http://users.chariot.net.au/~dna/kefirpage.html
Check out this site for more information on Kefir yoghurt, it is Dom's Kefir Site and he has a lot of information. Also contains links for products, etc. Hopefully you can find what you need.
Nourishing Traditions recommends making yoghurt by gently heating a qt of pasteurized whole milk, non homogenized, in a pan to 180 degrees, let cool to 110 degrees (using a candy thermometer). Stir in a 1/2 cup of good quality commercial plain yoghurt, place in a shallow glass, enamel or stainless steel container, cover the container and place in a warm oven 150 degrees overnight. Transfer to refrigerator, use paper towels to mop up any whey that exudes during the day and your good to go.
This book also has a lot more fermented food ideas and foods to deal with health issues such as yours.
Good Luck