If you are interested in getting the CGRect
of the currently selected cell in the collection view you might use:
CGRect rect = [collectionView layoutAttributesForItemAtIndexPath:indexPath].frame;
And after that you can display your popover from that rect
using presentPopoverFromRect:inView:permittedArrowDirections:animated:
of your UIPopoverController.
And yes, you can always dynamically load a VC from your storyboard if it has a storyboard identifier associated to it:
UIStoryboard* storyboard = [UIStoryboard storyboardWithName:@"YourStoryboardName" bundle:nil];
UIViewController* vc = [storyboard instantiateViewControllerWithIdentifier:@"YourIdentifier"];
In case you are calling the code from a VC loaded from storyboard itself, instead you can use:
UIViewController* vc = [self.storyboard instantiateViewControllerWithIdentifier:@"YourIdentifier"];