I can give you some swamp milkweed seeds. I have three kinds and will give you some of each. One is from a garden centre cultivar, 'Soul Mate' (and I may have a few white 'Ice Ballet'. I have local swamp milkweed seeds and some from up the Bruce Peninsula (Stokes Bay), which I find the strongest grower and most colourful.
E-mail me your postal address and I will get them off to you. I have found that fall sowing works very well and there was no advantage to starting them indoors early in peat pots or the like. The ones I started early were in fact surpassed by the ones sown the previous fall.
Of all the various species of milkweed that I have sown, the swamp (Asclepias incarnata), is the best to grow from seed.