It does take a while to 1. grieve 2. form a new attachment. We had two dogs, and when one was hit & killed, I started looking within a few weeks for another dog, too. And I felt guilty. After a few not so successful "trial runs", we finally adopted another husky. We really liked him from the start, but it took a while for him to get to trust us, as he was already 1 1/2 and came from a very loving husky breeder wher he was living with his family & littermates. It's been a year now and he is "all ours!" He gets along better with Star than any other dog she's ever been around.

You said your daughter already is very attached, this is probably really good for her. While it may take a little time for you, you'll grow to love him just as much. Our hearts don't replace the love of a cherished pet, but we don't run out of love, we just make room to love one more!
Congratulations on Cosmo, he sounds sweet!