I would keep going with what your plans are with tht lighting set-up. Much can be done with T8's without the need to spend big bucks on lighting. Deffinately buy some reflectors. You need them. You will notice much more light hitting your plants, and they will do better for it. Keep up with the nutrients, depending on your plants needs. You sword would benefit from substrate feeding and the hygro, just about both!
Is that Dupla24 your using? I hear its the ultimate of plant fertiliser?
Try
http://www.aquaria.com.au/catalog/index.php/cPath/6_21 for a reflector, if not, a DIY job wouldnt be too hard. Or even keep an eye out for a cheap light housing unit and use that.
I havnt heard of using a mirror before, but id say stay away. Reflectors reflect light, a mirror might concentrate light depending on its angle, and burn plants. (You could try though).