Why not pull the counter spells (mono blue) and put in Mana Leak? That way you aren't stuck waiting for 2 blue mana. Bad Moon is a bad choice as it only helps out half your creatures- instead add something that helps them ALL- creature enchants that allow you to draw a card if they damage (great for tap for 1 dam) or that remove a creature if it's caused damage (Sigil of Sleep would make both Prodigal and Zuran formidable, especially with Mana Leak) -would also work on the vampires in a decent way.

Tap to do damage for blue might be better with Somnophore (Creature) and Hermetic Study, which works better for the vampire, as it beefs them up for good, using their own powers. Then you can pull the 6 basic enchantments out and use Power Sink and more blue specialty things, draw cards or counters.

Pestilence doesn't fit as it's all black mana and it's counter to your own creatures, having it even in your sideboard is a waste, along with Drain Life -there's some good "vampish" black life-sucking instants or suicides or card kills, etc, that would work as a minor effect and keeping the B/U theme of tap to kill/remove while you get the big heavies out (maybe Sengier Autocrat x3 with Delraich or a Devouring Strossus or even Ascentent Evincar -who is a vampire legend).

Irini, Veldrane and Grandma fit better as sideboards.

What about underground River or more blue-black mana sources?

;)