Barfish
I was sitting in EXACTLY the same boat as you 3 days ago dude! I was combat daggers and only dishing out 1400 raid dps
I did ALOT of homework and found out that in wotlk:
1) Maces are prepped for shammies more so than rogues
2) Combat swords is supposedly the best raiding built, or IS it?
3) Mutilate daggers is the new kid on the block.
I've never played assassination before, and I respecced to mutilate daggers literally 2mins before our 10man naxx raid. I had to sort out rotation etc during the fights.
My raid DPS , without ANY gear change, went up from 1400 to 1900-2000dps. The down side is you arent as potant against mobs but you shine in boss fights!
I was going to buy weapons with my badges, but upon more reading I found out I was already sitting with the best weapons until 25man naxx. I have the Titansteel shanker in my MH (1.6) and the Librarian's Paper Cutter (1.3) in my OH.
The paper cutter (blue lvl 200) is selling on the AH for between 200-350g ... I'm considering putting mongoose on the extra one I have in my bank - since I already have mongoose on the other one i have.
I will then use the shanker MH during Mob clears and swap out for 2x 1.3 speed weapons during boss fights, both with mongoose. Mutilate spec is no longer about slow daggers. Use deadly poison on your MH and instant on your OH, they scale with AP as well

The speed increases will proc poisons like you can't believe! I was doing crits of 8700 ! I couldn't BELIEVE how many Combo points this build was throwing at me. One minute I'm on 0, the next instant I have 3 from a proc.
You don't want to get 'zerker yet. one of the 4 material types it requires is 10 shards that go for 90g each! 1500g for an enchant? No thanks.
Anyway ... I spent about 8000g on gear + enchants and ran lots of pugs since I dinged 80 last week, and I'm currently 180th on our server.
Last night before my other 4 upgrades I was doing 2600 dps... and I'm a serious n00b rogue. So give it a shot, see if it works for you.
Use the talent build for mutilate daggers as prescribed on
www.shadowpanther.net and let us know what your dps is like
You want to use the following rotation:
In stealth, just before the fight, hit HfB 3 times.
- Open garrote
- spam mutilate until 4-5 combo points and then hit S&D.
- from here on forth, if your S&D doesn't run out, whenever you hit envenom it will refresh your S&D automatically. It's a finisher that discharges ur stacked poison all at once - which is why its now very good to get fast daggers to stack them up again.
- spam mutilate to get CP's up and then keep rupture up whenever you have enough S&D to go around
As an assassin you have a skill called hunger for blood (HfB). It's a rage buff that gives you almost 10% extra damage and it stacks 3 times. It's important to keep this up along with S&D.
Get an addon called Cutup that monitors these 3 things. I scaled mine to fit below my health/energy bar so it looks neat and out of the way.
Good luck dude and enjoy!