If you do decide to get a longer barreled revolver, and you intend to only hunt deer, or bigger game, then I sort of agree with Raging480.
On the other hand, if you're planning on hunting smaller stuff, and game up to the size of deer, your gun will do fine if you shoot it well.
I think revolvers(scoped or not) should be limited to around 50 to 60 yards no matter what caliber you end up using. Some guys can shoot very accurately farther, and pretty consistantly too. Fact is though, we've all pulled pistol shots, and missed our mark enough, that I think trying a shot farther than around very extended bow range is taking too much of a chance on wounding game. It's one thing to hit a target every shot under calm practice, but it's all together different when it's a real life hunting situation.
If I was you, and didn't want to buy another gun, I'd practice with that 4" revolver from now till deer season, shooting not only targets, but any kind of small live critters like groundhogs or such, till I felt confident in my ability out to what ever range. Then when deer season rolls around, knock about a third off your confident range, and you'll kill any deer that offers a shot within that limit.
Your 357 magnum will kill any deer cleanly, and you don't even have to shoot hot loads to do it. If you don't handload, and don't want to spend big bucks on custom ammo, just run out, and buy any 158g SP load that shoots good in your gun. XTP-FPs are also great, if you can find them. Stay away from HPs, as they tend to open up way to quick on deer.
I've been killing deer every year for a good while with a 357 in both a 6.5" Blackhawk(getting ready to be cut to 5.5"), and a Marlin 1894C rifle. Not a single one has went farther than if they'd been shot with a 300 magnum, and most have fallen within sight of me. this picture is of one I killed last season with A Remington 158g SP.
