Start thinking about your own layout:
Make a list of elements of the old theme which are so important to you that you want them to keep in place and another list of elements which may be re-arranged on smaller displays.
Based on that, develop a new theme. See https://www.opensource-socialnetwork.org/wiki/view/1063/how-to-develop-a-new-theme

thats fine but the new version does not support that them then what should i do

We've been into that discussion many times before and I can only repeat: It doesn't work that way.

When you're living in an appartment of 40 square meters and the available space is already used to its limit, you simply can't move to a 10 square meter location and insist on placing your furniture the same way there. You HAVE to re-arrange your stuff and you HAVE to arrange with yourself which parts to keep and which parts to leave out.

but i dont want to change my theme so please help me

The recommended way is to upgrade to Ossn 4.x first, as it comes with fully response theme and built in framework already.