Exactly the same place you used to buy food - in markets, supermarkets, corner shops. Vegetarian food, both in its 'raw state' as grains, pulses and vegetables, and as pre-cooked meals, is widely available nowadays. Don't get caught up in arguments, just gather all the information about vegetarianism so you can calmly explain your decision. Then try introducing them to some of the delicious meat-free meals you're enjoying and see if you can win them over by setting a good example. But realistically speaking, few people can go from being a meat eater to a vegan overnight.
Vegetarianism is a very important halfway house.
And even if you never go on to being vegan, you've already made an impact and saved the lives of many animals simply by giving up meat. Far from being hypocritical, you're making an effort to change the way you live for the better. How far you go with vegetarianism is up to you, but however small the step you take, it's not wasted. And don't feel that you have to become a perfect vegetarian overnight. If you forget to check the ingredients list and realise that you've just eaten something containing gelatine , don't feel that you've failed.