How to find search within RichTextBox to get string from cursor position?

In a richtextbox, my cursor is in the middle(any place)

I wanted to find out the position of cursor.

From there, I wanted to find a particular word  or string or char (any line above the cursor) on left of cursor and make it a start point

Similarly, i wanted to find out particular word or string or char on right of the cursor and make it as end point.

Then, i wanted to cut the string between start and end point.

Is it possible If so,
How can i do it Any standard call, or some regex command

I am using Visual C++ 2003.

Thanks,

Jil.