when it comes to plants.. you can take it as far as you want to really. growing plants in an aquarium can be a very complex subject. You can grow a few plants in a low-tech setup with little maintenance or you can grow a whole whack of hard to grow plants in a high-tech setup which requires alot of attention. Its really up to you and what you want. So first ask yourself, are you willing to put the time and effort into it. If so the next step is to find out what you need equipment wise, then decide if your willing to put the money into it. From there on you need to do a lot of reading and asking the proper question. On the other hand if you want minimal work and just some nice looking plants(which seems like the case), then my suggestion is to stick in a few easy to grow plants and maybe dose a trace fertilizer such as seacheam flourish or another product.
Goodluck.