Regex pattern for date

Regex pattern for date

I have the following String:
vitals.date_created==2013-7-3 11:23:32
I am using the regex
([a-zA-Z0-9_]+[$.]?[a-zA-Z0-9_]+)+[><=]=?[a-z0-9A-Z'\\.@- ]+
but the regex doesn't work.