MOSFET? MOSFET. Also, try a MOSFET as has been suggested by several people.
The entire package of that uln2003 is not going to be able to handle 1.5 Amps of current. So, despite the fact that numerically 3*500 = 1500, it still will not handle that current.
Also, MOSFET? As btbass suggested: VNN3NV04 for example.
As far as I'm concerned, those ULN200x things are nice enough for a few hundred mA when you want a quick fix. But 1 Amp and above is far easier to manage with a FET.