You're in trouble. Here's how I envison the combat:
Round 1: Summon Gelugon
Round 2: Meteor Swarm (24d6, for an average of 83 damage, no save), gelugon uses Cone of Cold (13d6, average damage: 53 on a failed save. You have a +9 reflex, so you have a 60% chance of saving against the DC 18 cone), so you're looking at two massive damage saves right there, in addition to having 14 hp left.
Round 3: Repeat Cone of Cold, finish with physical attacks, fireball, wall of fire, etc.
Good luck. Note that the first Cone of Cold may be used on round one, depending on whether your DM thinks that a creature brought into combat this way gets to act that turn or not.
-Tiberius