Second George's remark about an adjustable stem. If you have no experience with sitting upright, you'll actually need the adjustable stem for quite a while before you're tuned in to the new ergonomics, which is likely to involve more than just a handlebar switch. You'll also have to tune in your seat height and angle and very likely, if you use a layback seatpost, change the seatpost. And they all interact. So count on using the adjustable stem for many weeks rather than a few days, until you have the perfect attitude on your bike, especially necessary if you already have trouble anywhere between your coccyx and your head.
The German supplier Humpert makes a very solid adjustable stem that I used permanently on a touring/utility bike because I was under the physio's care and what my back could take on any day was variable quantity. Kalloy (Uno) makes a cheap toollessly adjustable stem which you might find very convenient.
Unless you can source and afford a fancy Nitto, the most commonly available good North Road bars are made by Kalloy-Uno of Taiwan; they're a big OEM item on famous brands, so they're not too pricey if you want just one. Your local bike shop likely has some they threw off new bikes for people buying their first bike on the government scheme who thought they'd look racier on drops. That's how I sourced all but one of my North Road handlebars except the one which came with n'lock setup as OEM supply. Just ask at your LBS. If you want to spend more, Humpert makes a huge selection of attractive handlebars in all the styles; I've had them on very upmarket German bikes and they're the bee's knees and very good value too, especially the stainless ones.
Note as a matter of geometry that not all the nominal rise in North Road bars is available to bring your hands higher on the grips: some of that rise is lost because the grips have to be angled somewhat downwards for the kinesthetic experience.
Good luck.
