Turns out I need to make a weapon +1 in order to kill were rats. Any idea how to do this?

You can't "make" a weapon into a magic weapon (which are denoted by having +X to hit and to damage); you need to either buy or find one.

There is one exception, provided that you have a certain set of teeth that you can talk to; if Morte is at a high enough level, you can tell the teeth to become a magic weapon.

I guess I may be screwed then, Stuck heading to Lorthar and trying to get past the wererats but I can't kill them.

Depends, who do you have in the party and what weapons are you carrying? Iirc, Dak'kon's blade is a magical weapon; also, magic spells can still hurt monsters that are immune to non-magic weapons. If all else fails, I believe that there is a spell that gives TNO a significant bonus to hit and damage; not sure that it actually turns your fists into a magical weapon while it is active, but it's worth looking into.

Actually, why are you trying to kill the rats in the first place? You should be able to get by them without a fight.

How does one manage to get that far without finding (and keeping) any magic weapons?

Morte had the Junk to use the buried village portal so I can't get out that way and the Wererats are blocking the bridge to Lorthar and I cannot damage them.
I have Annah on my team, trying to recruit Ignus. This is my first time playing the game.

In which area exactly are you ? Below Lothar's house where Mantuok is ?

If you are talking about the bridge I think you are, try talking to the Wererat Mantuok; he's the one decked out in fancy looking gear. If you are working on behalf of Lothar, you should be able to talk him into letting you pass.

Yeah, I may have made him angry at me for refusing to hand over the skull.

Ok, so that entryway is screwed (I'm presuming that by "angry", you mean that they have turned hostile); try retreating to the Buried Village and exiting Ragpicker's Square (you'll find some junk in the Trash Warrens that will let you use the portal into the Square); now that you have helped the Alley give birth, exiting any area of Sigil will allow you to quickly travel to any area of the city by selecting your destination on a map.

If all else fails, try letting TNO die and see where he ends up; can't guarantee it will help, but it's worth a shot.

Wow thanks, That worked!
Now I have Morte back and I have to go find Ravel. Cheers.

Good to hear it :)

Just a heads up, there will come a point where the game will mention that you might not come back for a while; this is the understatement of the century. If you get to that point and feel like you have unfinished business, take care of it first; in your case, you may want to look into picking up some magic weapons.

So what you're saying is... Knowledge can change the nature of a man? *ducks incoming internet tomato*

No worries man, I'm not doing too well at the game obviously. This is my first isometric RPG.