Well...he starts out with a Vanillish. Shouldn't be to hard to beat; just use Emboar's Heat Crash. The next pokemon he sends out varies. You can probably take out both his Beartic and Cryogonal with either Heat Crash or Fire Blast.
So that takes care of the 7th gym, now for your team. I only have a few suggestions for it.
Archeops isn't too bad but get him to level 45 and teach him U-Turn or use TM Rock Slide for AncientPower. It's not the best move, even when it does raise all your stats.
Seismitoad was a good choice; I have one myself. Just get it to level 45 and teach it drain punch for Muddy Water and teach it either Acid, Sludge Bomb, or Sludge Wave for Bubblebeam.
Emboar is pretty good but why did you teach it Fire Blast? Since it has horrible special attack I wouldn't even consider it. Teach it Hammer Arm or something with a Heart Scale.
Eelektross is pretty good, but teach it Thunderbolt instead of Thunder. It is WAY more reliable. Possibly Flamethrower also.
Reuniclus is okay but teach it Focus Blast and Shadow Ball. Those will provide good coverage against Dark and Ghost types.
Other than that you have a great team. Keep training and you will destroy the elite four.
Good luck =)