We went to three close family funerals during my daughter's first year - total nightmare! She was 3 months old at funeral #1 and wore a pale yellow and white dress (it was summer) with white/black trumpette mary jane socks. I thought it was fine and she seemed to blend well. At funerals #2 and #3, she wore this dress:
http://www.rufflebutts.com/black-corduroy-jumper-ruffled-dress.html with the same accessories (tights, undershirt, bow) as the model. She was 6 months and 11 months, respectively.
I don't know if you want any funeral advice but after going to so many, I would just make sure that you have another family member or close friend who can be ready to take the baby if she starts fussing, especially if you were close to the deceased and don't want to have to leave halfway through. If the funeral is during naptime and she is on a set schedule, you may want to think about getting a sitter (learned that one the hard way), otherwise you should be fine to bring her. Make sure you have a few toys, plenty of pacifiers bottles etc. Good luck and I am sorry for your loss!