Yeah, firing any kind of direct effect weapon from 1 or 2 AUs would be fairly pointless. Lasers and particle beams would be scattered, diffused or partialy blocked by space dust amd micro meteors, while any projectiles would be pointless, as they could easily be dodged with a few random course changes as it would take hours or even days for the projectile to reach its destination.
On posibility would be a swarm of near relatavistic missiles. Any single missile could be defeated by anti-missile lasers (once the missile was within range) but if a swarm of missiles (perhaps more than 1000) was released at the same time, and accelerated up to near light speed... There would be problems with guidance, manuvering at that speed would be difficult, but some of the missiles would be likely to hit something. A smaller swarm (say 100 or so could be used traveling at a slower speed but equiped with stealth technology (either anti radar tech or cryoarithamatic engines).
For the satelites try to think of them as civ III spearmen. Their only real use is as defence units, sure you may move some of them to a weakly defended city in an emergency or as an escort, but generaly they just sit and a city and wait to beat any attackers. Satelites would be the same, for the most part, cheap defenders of a habitat city. However, I'm thinking of making two satelite types, A smaller, box shaped beam weapon, usualy found in groups (1/2/1) and a large Super satelite, with a much more powerfull single shot weapon, perhaps a railgun, or fusion burst gun (leathal defending bombard 3 1/2/1). The super satelite would be a little more expensive, but would only be effective if used in combination with other deffenders (where it would be quite dangerous).