Making this change would require using eCart and some custom coding. This type of customization should only be attempted if you are comfortable with using eCart. The idea is that you would start by adding in the text fields to the add to cart form. Next you would need to update cart object to include these new columns. Once you have done that can edit the add to cart server behavior to bind the new fields to the new columns.
This will get the info into the cart, the next things to do would be to update the display manager. This will require some custom coding to add in the bindings for these new cart columns. An easy way to do this woud be to drag and drop the new column values where you would like to see them in the cart display. You would need to update all of the cart displays including the confirm and receipt pages.
To store the details you will need to edit your database to add in the new columns in the order details table. Once you have done this you can modify the store order details server behaviors on the confirm pages to store the values in the newly added columns in the order details table.
This is an advanced update to the PowerStore and I would not suggest attempting this without an understanding of these steps and experience in using eCart. We cannot support this customization but we can give you pointers if you need them.