Ok well, thats roughly 1.5 watts per gallon. You could get away with a fair few plants with just the addition of ferts.
In my little low tech set up I successfully grew various Swords, Crypts, Ambulia Aquatica, Hygrophila, various Mosses, Red Myriophyllum and Rotala Indica but that was with the addition of TPN+ fertilizer every other day. I now have a Nutrafin CO2 kit added aswell as it was sitting in the cupboard and growth is amazing. The good thing about low tech is plants such as Myriophyllum and Ambulia and pretty much any stem plants that will be happy with lower light will stay very bushy and thick as supposed to high light where they will need constant trimming to keep them thick.
If you have a look on the Tropica website (www.tropica.com) it will give you a huge plant list and pretty much lets you know what each plant needs to flourish, there are a few aquatic plants not on the list but I'm sure it will help.
As for substrate sand will be fine so long as your not growing things like HC Cuba and Staurogyne, pretty much any plants that need nutrient rich substrate. As long as you have a couple of inches deep the sand will hold the plants just fine.
As for ferts, I would use TPN+, you can get it from any decent online supplier, just make sure it has the + and not plane TPN and as long as your photo period is no more than 8 hours and the tank gets no natural light from windows etc you should be fine and hopefully algae free.
Oh one more thing, if you buy swords and they look like they're dying after being in the tank a couple of days, don't worry, most swords die back a little and then come back quick as they are changing environment.
Hope all this helps as it took forever for me to type lol.
Steve