As Gabandit12 said in his post, the Stock Pilots that came on your bike are a great tire. As of now, with your limited riding experience, these tires will fit your riding abilty well. In addition to that, they will probably be cheaper, and be readly available at your local dealer, as he won't have to order your size/rim width due to the fact that most dealers keep a ready supply of oem tires in stock.
As for changing only the back tire, that too is a no-no. Front and rear tires are engineered to work together by the manufacturer and have a certain shape, or profile as we call it, to the outer carcass. If you don't use the same model front and rear tire, or even a worn front and new rear, you could possibly negatively alter your bikes handling due to the profiles of the tires being different (i.e. 207's have a very triangular profile and have a tendency to transition to lean faster, but are less forgiving at the edge of traction; whereas the battleax series has a more rounded profile, transitions or falls into lean slower, but is a little less likely to pass you on the track/street abrupty at high lean/throttle application).
I know there are a lot of riders out there who go and buy super sticky race rep rubber, but those tires have a higher operating temp than street oriented tires, and must be ridden hard before coming up to temp and providing optimum grip levels. I can't count how many $350 super sticky tires I've seen that were worn flat to the cords in the middle, but didn't even have the coscoat worn off the edges, what a waste of money.. Most of those riders didn't come close to using the rubber anywhere near it's limit, yet have to buy a new tire every 2000 miles.
I know there is alot of pressure in our sport to have the best, and look the best ( I call it the pose factor, all of us are influenced by it to a greater or lesser extent ), but don't be pressured by so-n-so on his (insert any sportbike) who has the race rep Pirelli Dragon Corse tires mounted on his bike. Even if they say something stupid like "You stayed with the stock tire?" (the manufaturer wouldn't fit the tire to the bike if it wasn't a capable tire), you can just grin and laugh at him as you point out the trick steel/kevlar braided brake lines and carbon tank protector you bought with the money you saved..
sorry to be so long, just passing some knowledge..