How about looking further than just the Aston placement website? Google companies, look on their websites, try sending speculative letters and cvs etc etc....
I know it's a heck of a lot of work and effort when you really don't have the time (been there, done that, got the tshirt and now doing it all again for grad jobs!) but just try and do a bit here and there, especially if you're doing speculative letters it doesn't take too much time once you have the basic template to just tweak it here and there to personalise it and you can send it out to loads of places.