Oops sorry Rachel
Well as I said I'm still pretty new to the whole planted tank thing myself - but having the smaller version of your tank, I know for a fact that you will struggle immensely to grow your current plants under your current lighting conditions.
Also, as the tank is only 8 weeks old, it's barely established but you will almost no doubt start seeing some algae growth pretty soon.
You should check out the
Planted Section and the pinned threads at the top. But as a starting point, have a look at
Lighting levels.
It's fairly straightforward to upgrade the lights on your tank and
this thread where Jimboo showed how he upgraded his Rio 180 should give you a very good idea what to do. The only slight problem with the Vision model, is that you won’t be able to have the same length fluorescent tube at the very front (due to the curve of the tank). So I'm not entirely sure which one will fit yours - perhaps a 30 Watt but certainly a 25 Watt. But at the back, you can certainly add another 38watt (with reflector).
And then by adding reflectors at the same time (very easy as they just clip on) you will have a far greater chance to grow your plants.
In essence you will need a starter unit for each addition tube you add in. To give you an idea what they are,
here are some examples and prices on Aquatics Online. The same goes for the
reflectors.
Why don't you pop by the planted section if you are interested, and post your water stats - Nitrate, pH, kH, gH and also if possible Phosphate readings. Though at the moment the latter isn't that important. It would help if you could give your tapwater readings as well as your tank water readings.
If you are fairly new to fishkeeping it can be a lot to take in, and it certainly took some time to get my head round the whole "planted" thing. But seeing those beautiful planted tanks (and you have a great one to start off with!) makes the effort worth it.
Good luck