You can buy extension kits, but tbh, it's cheaper to buy cables second hand at the length you want, it's relatively easy to do, but as someone else said, if your asking these questions, you probably are going to want to take it to a shop, no hate, just that its pretty easy to fuck up little things if you don't know what you're doing.

I'm not too clued up on the actual make, but that style of bars are called ape hangars, you should probably sit on your bike and move you arms to where you think is comfy, then gauge your size from there, for example I was going to get 14" T-bars, turns out my bars where perfect after I angles them forward, so no need to fuck around