Need help changing shifters
 

So I am completely new with road bikes and barely know what I'm searching for half the time.

Recently I've purchased a road bike off amazon(the Vilano Aluminum 21 speed) and had no idea that the gear shifters that I wanted, which are the sti gear shifters, were not on it and rather they had Shimano A050. Mainly because I didn't know what I was searching for but but I knew what I wanted.

Currently, I'm trying to find sti gear shifter for a 3x7 bike but want something more modern than the shimano rsx sti. I've also read about using an 8-speed shifter by creating a "phantom gear" but am unsure on how that works.

All help is appreciated. Thanks

Best way to go would be sell your present bike and get the one you really want.