how do i get to the secret island where i can get latias on pokemon ruby and how can i get jirachi

im having some trouble when i put the gamesharks in my pokemon rom

I am about to battle the fourth gym leader and I don t know what pokemon to use- I have;
Zigzagoon
Zubat
Seedot
Wurmple
Aron
Loudred
Silcoon
Poochyena
Makuhita
Minun
Nincada
Oddish
Gilpin
Electrike
Volbeat
Roselia
Wingull
Sandshrew
Spinda
Skarmory
Zangoose
Trampinch
Numel
Swablu
Combusken
Swellow
Kadabra
Linoone
Geodude.
In case to didn t know this gym leader has normal pokemon

http://www.amazon.com/Ruby-Rox-Tuxedo-Dress-Ruffle/dp/B0013J1F4W

or this dress- but in black

http://www.amazon.com/TAMBER-DRESS-Bridesmaid-Formal-Prom/dp/B00144R6OE/ref=pd_sbs_a_title_19

is it possible to complete the pokemon emerald pokedex (hoenn region) without buying ruby or sapphire?

can you do it with one system?