In the Ruins of Alph, to obtain the Old Amber you need Rock Smash. You may get the Helix fossil if your playing HeartGold, or you might get the Dome fossil if your playing SoulSilver. You Also might get no fossils or, you get the old amber. But in a way, it seriously doesn't matter if your just starting the game because you need to go to the Pewter City Museum and have some guy in the right of the museum that looks like a scientist get the Pokemon from the fossil. And, you won't get the Old Amber each time. It might take a few days before you can get one.

I easily got 2 old ambers it took like 5 minutes just keep smashing the rocks until you find it

U could rock smash the stones at the ruins of alph 2 find an old amber, but it may take a while 2 find one, or u can do what i did, and migrate one from fire red, i migrated mine at level 5, and u know how when u recieve a traded pokemon, and it's exp points r boosted?, it's the same thing with migrating pokemon from games like pokemon fire red, leaf green, emerald, ruby and sapphire, it levels up faster, if u can get on with pokerus, then u would be even better off, and it will have some ridiculously high stats, especially it's speed :), hope that helps man