To be specific though, you won't get the money back as a direct refund if they did do a wipe, you'd get it as a battlenet balance that you could then respend on whatever Blizzard products you wanted, including just rebuying items in HotS of course.
Yes you will keep it when the game is fully released. They said that there are no planned wipes, but even if they do have another wipe all real money and gold purchases are permanent and 100% final. No repurchase of bundles, heroes, mounts, or skins will be necessary.