I think she needs at least 600 range since shes got no escape, lucian twitch sivir and vayne all have a way to get away. Shes fun to play but needs to be fixed.
maybe nerf her ap buff her ad ? or make her do more damage from plasma since it takes forever to stack and she does missing HP% damage.
Her upgraded E provides decent escape but even then it has a fairly high cooldown.
But yeah I agree Riot needs to give her higher range because as of right now she's getting outranged by almost every ADC.
I think she will get some buffs next patch hopefully.
As for the passive just buy this 
, you will be able to proc it every 3 times.
ohh. I didnt notice that stupid range. that would explain things.
auto range buff!!
but not to 600. thats just silly. 550 would be just fine
I disagree with your reasoning and with your numbers, but she does need a range buff.
500 range is too low on any marksman.
