Transplant immediately! My plants at 3 weeks were at least double that size. There is no way those cups are allowing for sufficient root growth. Get some 3-5 gallon pots and mix some soil soon. Also, what Kelvin is that light, it may be worth investing in a 6500K CFL (looks like you have a warm 3000K bulb in that pic) to get some blue wavelength on those babies. Whatever you do tho, transplant. Other than that, it looks like those plants are definitely save-able. Good luck, hope it all goes well.