I am a British Citizen and my wife is Syrian. She has a Spouse Visa for the UK and we're currently living together here in the UK and we had a little baby girl two months ago

Wife also has a Schengen Visa because of a holiday we took to Spain.
The Schengen Visa is valid until the end of Feburary 2016. Can she travel to Austra to meet her sister who is married there?
Do I have to travel along with her? Or can she travel alone with our little baby girl?
Any help and advice would be greatly appreciated.
Thank You