Aftermarket deck or amp which way to go?

[YarisSedan]

Okay so I dont want to go all crazy. I just want something that sounds pretty good without breaking the bank. I spent 60 bucks on some component spearkers for the front. 6.5 subs in the doors and some tweets. For what i spent they sound 100 times better than the factory speakers. But the subs dont have enough power for them to sound good when the volume is turned more than 40 percent.

Would i get better results just using a amp to my factory deck. Or just changing out the factory deck to something aftermarket with more power.

Since the cost of both is pretty much the same. Keeping in mind i have a intergrated stereo. So i kinda would like to keep it factory and just run a amp.