Confirm the model of the shifter you have. It can be found under the hood as shown in the the pic. On the outer side of the shifter.




Changing the shifter would be one of the more expensive parts, along with possibly needing a new rear derailleur if you go 11 speed, (very likely).

Brake calipers and front derailleurs are usually easy to replace, with the shifter info, some recommendations can be made.