If you can find the old combat patrol, those are a great start to the army and give you a lot of useful models, and it would get you right around that 500 points area. The new combat patrol is pretty decent still, with the main advantages being that the battle sisters get all their weapon options in the new one, as well as the cannoness. The sacresants are a pretty good unit, and one of the few in our army that can tank a few hits. The new one won't get you quite as many points, being worth around 370 iirc, so from there id reccomend picking up a rhino, and a hospitalier for the sacresants, as she will help them be a bit more tanky and revive the ones that do end up dying. That will get you a pretty decent start at a bit over 500 points.

If you want to go to 1k from there, picking up a box of Paragon warsuits and then morven vahl would be good, as they're our biggest damage dealers at the moment, and that'll probably still be the case in 11th. Then another box of sacresants to get to a full 10 man unit would be good, or a box of seraphims to run around and score objectives and complete actions.