The Eagles returned home for a game against the Cowboys.  They scored first with Michael Vick hooking up with Riley Cooper on a 2-yard touchdown pass for a 7-0 lead, however, the Boys responded with Tony Romo finding Felix Jones on an 11-yard pass for a 7-7 lead.  Then increased their lead in the 2nd quarter as Dan Bailey kicked a 30-yard field goal for a 10-7 halftime lead.  Michael Vick had been knocked out of the game and was possibly out for the season after going 6/9 for 70 yards and a touchdown pass.  Rookie QB Nick Foles would get his first NFL action and threw his first touchdown pass to Jeremy Maclin from 44 yards out as the Eagles retook a 14-10 lead while Henery moved the team ahead 17-10 with a 40-yard field goal.  After this, the Cowboys went back to work as Romo found Dez Bryant on a 30-yard touchdown pass to tie the game at 17-17.  Then the Boys retook the lead with Dwayne Harris returned a punt 78-yards for a touchdown for a 24-17 lead followed up by Brandon Carr returning an interception 47 yards for a touchdown and a 31-17 lead.  The Eagles then got back to work with Stanley Havili 1-yard touchdown run (with a failed PAT) to shorten the lead to 31-23.  But the Boys wrapped the game up with Jason Hatcher's fumble recovery in the end zone for a final score of 38-23.
Question: How many more points were the Boys leading by at the end of the game than they were at halftime?
Answer: 12