You can achieve this target using configurable products.
Follow the instructions given in below link.
I got into another problem again. Not related to above issue. But checked just now and found when i add product to wishlist, the page content comes blank. Everything comes except there is no wishlist list and no message of addition.
Also, how to get cart quantity at custom location. i tried this but no success.
I found this on one phtml
<?php $_cartQty = $this->getSummaryCount() ?>
Hope to get help on this one too.
Searched everywhere not found.
Thanks in advance.