Change Class in Combat

[whassumattuh]

I am a Human equipped with the Horny Helmet, which grants me a +1 Bonus and grants a +3 Bonus to Elves. I kick down the door and fight a monster and I am losing the battle by one combat level. I have an Elf card in my hand so I decide to become an Elf. I was using the Horny Helmet before the combat began (i.e., I did not equip or un-equip the Horny Helmet). If I become an Elf in the middle of combat, do I get the +3 Bonus?