Poa is an annual and will die in the summer. If you don't want to wait, you can spray it with roundup and reseed. For such a small area, I would probably kill it now and patch.

Poa germinates in the fall, so it is just something that comes along with fall seeding. You can use a preemergent this fall so that it doesn't return next year. You probably will want to buy a bag now and store it because the box stores often only carry it in spring.