I have a recently installed a different shopping cart software which changed my url from mysite/store to mysite/store/home.php. It already redirects without the need of htaccess hack from mysite/store to mysite/store/home.php but I am not seeing the pr come over yet, should it happen soon or do I need to modify the htaccess
PR is given to the url that you see in address bar. Its better to stick with the previous url, get someone who knows how to use mod rewrite and he can do it for you.
Yes of course, htaccess modification is essential if you want the pagerank to be transferred, but the best bet is to retain your old url if that is possible
PR won't update for ages. I recently did the same thing. As you can see, www.coffeesh0p.com has a PR of 3, but most of the other links on the page (EG: www.coffeesh0p.com/shop/cannabis_seeds/) have PR N/A. That page in particular used to be /Shop/6/, which has a PR of 3 before I moved everything round.
if you have used 301 redirect, your pr will be transfered but you have to wait. google did not updated the page rank until now
Give some time to Big G to make a PR update. Doing 301 redirect will help, but you cant "hurry up" the Big G