I had my last period at 11.12.2011 so can I get pregnant 3 days before my period ?

Yes.
Unlikely but possible.

Not usually but all depends if you ovulated late most woman usaually ovulate 14-16 days into there cycle

Unless you have bee doing basal temperature readings long term and charting them. (only women TRYING to get pregnant usually do this)... you have no idea WHEN you actually ovulate. Sperm can remain viable for days... the egg can remain viable to some time into the cycle as well.