Cube enhancement

Hello

I want to enhance one cube. Its already having huge content. Now the steps what i follow is as below.

1) Create a new cube with additional info objects.

2) write update rule for the same.

3) Change the communication structure to incorporate new IO

4) Modify the transfer rule also.

5) Enhance the datasource at source system level.

Now what i will do is i will use the previous cube as datamart and create one export datasource and populate the new cube.

But since my old cube is having data till say today, can i get the data for added info object in my new cube till today? if yes how can i go about it?

Regards

Sriram