Just some questions before NG+

hi.

ive now beaten all bosses and before new game plus i want to do as much as possible on this playthrough. my goal is to get platinum.

i play offline (no internet on ps3)
so is it possible to "farm" slabs or are there any changes in the new patch. i dont know my current version (i think its that one before the newest). http://darksoulswiki.wikispaces.com/Upgrades this is the list of the upgrade stones.. tell me please if there are some changes in the newest patch.

i killed on my current playthrough all bosses include dark sun gwyndolin. is it still possible to join the dark wraiths and blade of the darkmoon covenant?
and i need emit force from siegmeyer of catarina and i also need to do the reah of thorolund quest..
and my question is: is it still possible to join the covenants, meet siegmeyer and do the reah quest or is it impossible for this time until i started a new game?

so that was it.

sorry for my "dumb" questions and the broken english. i'm from switzerland.

thanks for help

You can't join the Darkmoons if you killed gwyndolin. You can't join the darkwraiths if you've given the lordvessel to Frampt.

Slabs are a very rare drop from the darkwraiths in the new londo ruins. Otherwise, you only get one from the Stray Demon, and one from Siegmeyer.

Darkmoon is closed off for you since you killed Gwyndolin. Dark Wraith is also closed off I believe because you gave the lordvessel to Frampt and not Kaathe.

If you haven't killed off all of the crystal lizards in the hollow, they can drop slabs as well. I got 2 when I was there the other day.

okay and how about siegmeyer and reah?

Where you are in the game, I'm guessing that it's too late to help either Reah or Seigmeyer.

Like the guys said, you can farm slabs from the darkwraiths in New Londo, but it might take hours. You might not get platinum on your first playthrough due to the choices you take during one playthrough.
My suggestions are: try to upgrade all your demon weapons and special weapons, kindle all the bonfires to the max. Just before going to fight Gwyn kill all the NPC's unless you have an unfinished quest like Siegmeyer.

Note that you'll have to do at least two and a half playthroughs to get all the boss soul weapons, so don't worry about losing the opportunity for Seigemeyer and Rhea this time, just make sure you do their stories in NG+ or NG++.