I'm having trouble defeating the Elite Four in the first Pokémon White. I'm positive that increasing the level of my Pokémon will help a lot, but I'm also wondering if I should change my moveset up a bit.

That being said, I don't only want advice because of the Elite Four, but because I want an awesome team by the end of the game regardless. Anyways, here's my current team:

Emboar Lv. 48
Lax Nature
Ability: Blaze
Item: Charcoal
Flamethrower
Brick Break
Strength
Assurance

Simisage Lv. 45
Calm Nature
Ability: Gluttony
Item: Miracle Seed
Seed Bomb
Acrobatics
Bite
Shadow Claw

Zebstrika Lv. 43
Naughty Nature
Ability: Lightningrod
Item: Magnet
Spark
Flame Charge
Facade
Thunder Wave

Seismitoad Lv. 46
Sassy Nature
Ability: Poison Touch
Item: Scope Lens
Surf
Drain Punch
Dig
Sludge Bomb

Beartic Lv. 47
Calm Nature
Ability: Snow Cloak
Item: NeverMelt Ice
Icicle Crash
Surf
Brick Break
Shadow Claw

Rufflet Lv. 43 (Will evolve into Braviary)
Lax Nature
Ability: Sheer Force
Item: Sharp Beak
Fly
Air Slash
Slash
Shadow Claw

I would really appreciate any advice given. I know that there are some moves I may not have access to until after I defeat the Elite Four, so if there is another place-holder move you might suggest, I would be very thankful for the help.