That gym will be opened 1 year later, so this means you can't enter it in this hack, just forget it and go back to Amberyellow Town, go left to reach Mugwort Villa for your 6th badge, please.
The newest Version 2.34 was out for fixing the mega evolutions and adding new Pokemon/mega forms. Now about 8 new Pokemon from Kalos and 11 mega Pokemon are available in the Version 2.34. I choosed Charizard X form as the mega form in this hack, because I made its sprite eariler than Charizard Y. About the item for mega evolution, simply go to the Generator Room to meet and battle Engineer BC, he'll give you two items for it after you won, one is for evolving and another one is for canceling, so that you can only have one mega Pokemon in your team. You can only get new items after you canceled the previous mega evolved Pokemon.
Thanks for the info i feel dumb for forgetting were to go.