Is there a bolt-on way instead of welding? I do not have access to a welder, I know welding is the way to go though.
For 2 x 6 rockers, no. Even if you replace your current rusty rockers, they need to be welded. Some people use rivets and bondo, but that is a VERY bad method on "fixing" (a.k.a. destroying) a unibody vehicle. Unibody vehicles REQUIRE rust repair panels to be welded in, not ghetto- fixed.
Because your rockers are rusted badly and need to be replaced, you cannot bolt on even the kind of aftermarket rock sliders CJ7-Tim posted. They need the rockers and uniframe to be in good condition.
..in other words, because you need to do welding anyways, the best method is to use 2 x 6 box steel. A lot stronger than stock, act as rock sliders as well, and are in fact easier to weld on than using pre-formed sheetmetal OEM- style rocker replacements.
Even if you can't weld, go buy a $50 grinder at Lowe's. You can cut out the rockers, trim down the 2x6,flat bar to cap the ends, ect and prep everything to be welded and find a local welder to burn it in for you. The prep is the pain in the *** part that would get expensive to pay someone else to do. Should save you a good bit doing that yourself. Post in the regional forums too, you might get lucky and find someone on here willing to weld them in for you for free. Jeep clubs are good for that sort of thing too.
I am pretty sure they saved me from at least one roll over. It's also nice to have more overhang to step on. There's enough there that I can walk along the length of my Jeep by walking on my sliders. Super nice if you're axle deep in a mud hole to be able to shimmy around the outside of your Jeep without jumping in. Some might say that's half the fun I guess. I also like that there's essentially two rails per side with a gap between them; it makes me feel that a hi-lift is a little more secure in there.
Every place I know of sells sliders in unfinished bare steel, and some offer powder coating as an option. Just be sure, no matter whose you buy, not to skimp on whatever paint/coating you choose to go with. What a PITA to have to strip, sand, and prep those over again after they're installed.
AJ makes good stuff. You might find some ****ty reviews out there if you Google him, but it's because people jumped the gun thinking he was scamming people a while back when in reality his house and workshop caught on fire and burned down. Outside of that I've never seen any complaints about him or his stuff. I think he's very fairly priced too, especially compared to some vendors.