If you go down to the place were you can take pictures and dress up you pokemon there will be a guy there and he will give you a TeamRocket uniform
On Pokemon Gold? SLOWPOKETAILS
you will get it from lance team rockets headquarter
Where the Pokemon Salon is, a newcoming Team Rocket Grunt will give you the Team Rocket uniform.
There isn't one in Pokemon Heart Gold and Soul Silver, there's just 1 or 2 rockets scattered.
it,s in goldenrod city.( at the very top )
you can not do that sorry
Red and White
It seems like your talking about Pokemon Red rather than Pokemon Gold because in Pokemon Red,Lapras is in the Rockets hideout in Silph Co in Saffron City where i believe your given Lapras by someone (Bill??) near the top of the building... But in Pokemon Gold,Lapras is found deep in Union Cave which is between Violet City and Azalea town, But the Lapras is only there on Friday Mornings,so if you go there any other time the Lapras won't be there...
Go down in the goldenrod tunnel then go to the guy who gives you the uniform. He's a bald guy i think.
The amulet coin is in the basement of the pokemart in goldenrod while you defeat the rockets that take over the radio station
One you cant keep the outfit. Two its in the underground tunnel in goldenrod city. And three you get to take a picture with your Pokemon party wearing the outfit.
you go to goldenrod and go to the goldenrod tunnel and talk with a team rocket man he gives you there team rockets uniform then you go to the radio station and talk to the guy and he will battle you then you keep going up flights of stairs then you will battle a guy who is actually a girl then you battle her if you win you get the basement key