Change format references


I need some help with something. I have to change the format of my citations and I am not sure how to do it. Every time that cite something I have this format, eg:

Sukumara andPandey 2009


Eisberg 2006, Panda et al., 2011

What I would like is to have a space between “and” and the second author along with a comma before the year (eg: Sukumara and Pandey, 2009). Also, I would like to have this punctuation ; to separate the citation of two diferent papers (eg: Eisber, 2006; Panda et al., 2011).

How could I do it?.

Thank you.