Web development using c#, asp.net

I need to add some functionalities (like adding messaging support) to an existing website. This needs to be done in about a months time. The only thing I know is about it is that the website is built using c#, asp and maybe a little of java script. Also, it may include working with database (I assume) as I need a user messaging feature. I am currently familiar with java. Thus, I want a right strategy that can help me learn the required to implement those functionalities. Also, will it be possible to achieve this in a months time, if it's a little unrealistic, I'll consider dropping the project.