Gas prices in the Dayton region have risen again, and they are expected to keep rising throughout much of the next several months before topping out in May at around $3 per gallon. Average retail gasoline prices in the Dayton-area have risen 2.4 cents per gallon in the past week, averaging $2.15 a gallon to start this week, according to GasBuddy.com’s daily survey of 391 gas outlets in the Dayton region. The national average have 0.5 cents per gallon in the last week to $2.28 per gallon. Including…