You can extend the duration of your spells through concentration.

Benefit: When the duration of a spell enhanced by the Concentration Spell feat (called a concentration spell) is set to expire, you may instead concentrate to maintain it. When your concentration ends, so does the spell. Concentration Spell may not be used on spells with an instantaneous or 1 round duration.

Level Increase: +1 (a concentration spell uses a spell slot 1 level higher than the spell's normal level.)