few mm off centre is no prob, if it's a long way out, I'd suggest steaming the centre of it then clamping it bent the other way a tad.
it's easy to make a steam box from old insulation board or somesuch and a wallpaper steamer. Make a simple form to clamp it to, and get everything ready to clamp it as soon as you pull it out of the steam, you have to move quick, so try out out before you steam.
Yew responds well to steam bending, you could always take aut the twist, but it's harder to make a jig for twist removal.
If you are reluctant to try it on your bow, try it out on a bit of scrap timber first.
Del