Stock Upload & PO Upload

My Client is a Real Estate Client.

Intially at the time of SAP implementation, they have maintained their each Construction project as a Storage Location & they were maintained under the 1 Plant .This way they are not able to see the valuation of each Project individually.

Now they have decided to change each Construction Project as a Plant (as this way they will be able to get the valuation of each project).I have defind all the Project loaction at the Plant.

Now I need to know ;how to upload the current available stock in these respective plants (earlier which is available at the S.L.).

Also, How the Current PO will get transfer to each respective Plant. Do I need to create all the PO again. Is there any way to copy all the current PO's.

need reply urgently for this.