Apart from Brian (Saturday only) they will all be there from 11am/4pm on both days. For more info on the Memorabilia Fair, and directions to the NEC, try the Memorabilia website. Good luck to you - the site is badly broken and does not respond to me.
Doors open 11am (Saturday) and 10am (Sunday). Adults £7, Children £5 (or £10 for early entry - 9am - Saturday only). You can buy regular tickets on the door, or advance from the NEC Box Office (0121 767 4555 - booking fee 50p). With hundreds of dealers, selling all types of SF/Cult/Film/TV memorabilia, this is the perfect place to do your Christmas shopping.