Based on the message your friend shared, Lisa's cat (referred to as "Tatze" which is a cute nickname for a pet) has given birth to 3 kittens ("3 Junge bekommen"). Your friend is saying how cute the little ones look, and that she also wants a cat. So if you want to congratulate your friend on her new babies, it would be about 3 kittens, though they actually belong to Lisa, not to your friend directly.