ROA2 question here.
I've been through the swamps and am back in Lowengen. I have possession of the fake Salamander stone, apparently the real one I need is in the home of A. Sevenstone. No problem, until I get there and his house is stacked with powerful elves and more...way beyond what my crew can handle. All walkthroughs say to "reclaim the stone" and go on with the game. This seems impossible and I cannot talk my way through this one at the front door. Have I missed something here?
All spoilers welcome!

No, you haven't missed anything. You have to fight your way through there. That is the only way to obtain the stone.

Normally there is a 10 (?) day time limit in obtaining the stone after Gavron took it from you. Doing the swamps first doesn't seem to fit within those ten days. If you have no time limit, beef your party with poison and herbs. Money is easy, now that you can smuggel to lowangen. Candy is the most cost effective smuggel product, as you can carry 99 in each inventory slot.

Apart from that, the former "Commerce Hall", the one riddled with beggars, is an easy way to obtain some XP (only once). Apart from that, grinding is not an option, as you only cain miniscule amounts of XP after you encountered an enemy for the first time.

You probably didn't play RoA 1 before and started with a new Party. What is your level and did you create the chars yourself?

Poison in RoA 1 was broken and always an instakill. They fixed this for the later games. It still does hell of a lot damage in RoA 2 + 3, but if you are really in a twist, use the "Fear Poison", as this will make the enemy beeline for the exit. It does not make a difference XP wise if you kill an enemy or if he flees.

I don't use poison in my games, but it is a nice "last resort" if you are in a position like you are.

I know this is months late, so maybe you've moved on or solved your trouble or whatever, but here's the deal. You're in a bind :/ BEFORE you go to Lowangen, you really, really, really need to hit up the Dwarven Pit. Get your whole party the belts of +5 STR, and the magic, everfull water skin. Now you can have a combat speed of 7 for your whole party even with heavy armor; that combat speed makes a world of difference in closing with ranged units and maneuvering. Now, once you get to Lowangen, obiously all your stuff is stolen. You need to rebuy heavy armor for your tanks and use some poisons. If you're up for some cheese, you can drop off the most expensive pieces on a few characters that you create and move to the nearby temple just so they can mule goods for you. And your magic belts, your waterskin, the magician's staff, and Artherion's sword (I think...) won't get confiscated by the orcs, so you can carry those at least with impunity. Now, for that fight.

Use poison on your weapons, of course.
Your first spell in combat should be a lightning (blind spell) on a caster.
If you have a druid, use Evil Eye on one of the melee types (I like to pick Thorwalians or Warriors, but YMMV).
Have your tank(s) gather up the melee units and hold them while you beat the tar out of the casters and ranged. Keep at least one unit blinded at all times. If you have a magician with paralyze, use it, too.
Don't be afraid to split up any healing potions or whirlweeds among your guys and use them in combat. Ten life for the whirlweeds, and as much as 20-something from the healing potions, can make all the difference.
If you have Heptagon at a castable level, it's great to run your magician into the casters and call the demon (I always get a Zant). It'll go berserk and attack you, of course, but usually not before it lays efficient waste to the lightly-armored magicians, druids, hunters, and elves that hang in the back. And it can't do jack to a tank with 13 or 14 armor, so let it go berserk. Who cares.

It's a hard fight. One of the three most difficult ones in the game, in my opinion. But it can be won - just keep at it, and realize it may take a few tries, even with the "right" strategy. A few lucky spells on their part can ruin everything =(

you dont have any means to reload to the point before you tail the thief to the home of Sevenstone? I remember the fight being MUCH easier if you attack the home right after you successfully tail the thief rather than wait till later to attack.