Aerobars will not only make you slightly faster on the bike, but most of the time also make you a faster runner since you actually save energy on the bike that you later can use on the run....

1mph though... Interval training will do that... add 1mile full speed with 1mile rest and repeat 5-10 times. Next week, you increase the distance for the full speed but maintain the rest distance. The week after, another increase in distance for the full pace.... and so on. Will make you faster!!! but it does hurt... so make sure you do get sufficient rest days.