!!!!!THIS IS NOT A CHEAT!!!! Some body please help me!!! I really need..

Wow, good job getting Celebi! I had to trade my 1st shiny ever for mine at the Nationals last summer, but it was worth it!!
There aren't any Bellsprouts in Emerald or FireRed! You need to trade from LG to get one legally. To get Jirachi, you're out of luck unless you can get one from a bonus disc onto Ruby or Sapphire and then trade it over. (The disc will work over and over as long as it's into a R/S game that it hasn't been done in yet-I've given away tons at parties and stuff) I've heard you can get one after beating Pokemon Channel, but cannot confirm that since I haven't done it yet myself.
As for Lugia, & Ho-Oh, unless you get them out of GC games like XD or Colosseum, you need to get to Navel Rock. You needed to get the Mystic Ticket from the mall tour last year or at some Nintendo Event they were giving that out at. I don't think they'll be doing it anymore since they had stopped by the 10th Anniversay Nationals in August at the end of the mall tour, and you could only get the Top 20 (no legendaries except the birds and dogs) or a flying Pikachu at that event. Then they just gave out Mews at Toys R Us Sept 30th.
Deoxys is the same story, you needed an Aurora Ticket to go to Birth Island downloaded into your game from Nintendo into Emerald or FR/LG. Then you needed to solve the puzzle to get him, but you get the speed form in Emerald, rather than Attack(FR) or Defense(LG).
Mainly, unless you know someone who will be willing to give them to you (yeah, right! Unless you don't mind clones! Even those would be difficult to get...) you'll have to cheat to complete that Pokedex. Getting an Action Replay (or Game Shark if you prefer, but I don't have that one) and utilizing the warp codes or encounter codes seems to be the only option left, sorry! If you know someone with them, they can try to clone them in Emerald and give them to you if you can convince them! I'd do it for you or help you personally, but it's tough long distance...I can help if you are near Wichita Falls, TX until April, then I'll be in MD.
And you could have all my rare candies, too! My Zigzagoons and Linoones pick them up a lot for me and I never use them! There's one in Granite Cave, up that slope with the mach bike and go up the stairs all the way to the right. One is on that island thing without the tree in the water near cycling road(go right at trick house, then surf north at the first break in the wall on your left a few steps later).[Even better is the Itemfinder you get around there from your 3rd rival battle-that's how I found a bunch of them and lots of other good stuff-I've been meaning to make a walkthrough of all hidden items...] Beat the trick house on visit one to get another RC. Up the waterfall on Rt. 114 is another. There's one in the Magma Hideout. Up the top waterfall on Rt. 119 near the Weather Institute is another. There's one in Shoal Cave. Rt. 127 in the NW section where there are trees and 2 trainers. Rt. 132 in the western area above rocks and a trainer. Well, that's 8 right there! There's a few hidden underwater (and a bunch of heart scales), too, but you need the itemfinder or look for spots in the sand and stand (swim) over them and press A. If you had an AR, you could just put a ton into your game, by the way....
Let me know if I can help any further, OK, and if you're in my part of the country, I'll do my best to help you even more! I have no one to play with out here yet! :(

Check the cheat selection for this game, it might be there, but if it's not, then you wont be able to get thoughs pokemon.