Yeah, kefir is great. But watch out for any negative side-effects as you could have developed a milk intolarance. They say most of the lactose Sugar is digested, but if you are sensitive, you could get a bad reaction from kefir and yoghurt anyway.
I remember my digestive system used to be just too inflamed and sore to be able to handle the above, but maybe yours is different ;)
There is something called Sauerkraut over here in Europe, which can be bought in the health food stores. It's a form of cabbage soaked in probiotics in a glass, even my doctor recommended this to be my probiotic supplement of choice. This is also cheaper than supplements. If you do decide to invest in capsule form, choose a health food store which stores the different brands in the fridge. Left on the shelf, the probiotics die. Also, if I may recommend, choose a brand with only a couple of the main strains such as Lactobacillus acidophilus and bifidobacterium bifidum. Introducing too many bacteria strains at once could be too overwhelming to your system in the beginning.