Our galaxy itself contains a hundred billion stars

It's a hundred thousand light years side to side

It bulges in the middle, six thousand light years thick

But out by us, it's just a thousand light years wide

We're thirty thousand light years from galactic central point

We go 'round every two hundred million years

And our galaxy is only one of millions of billions

In this amazing and expanding universe

Milky Way is much smaller than that. The Andromeda galaxy is 2.5M light years away. Maybe that's where you got 2M from. The Milky Way is about 100,000 light year diameter.

If we somehow figured out how to travel at 1000x speed of light, I'm sure we'll be able to increase that number to 1 million, 1 billion, and beyond. Until we just stopped using "speed of light" as a frame reference because it would be a completely different method of traveling (like instantaneous through a wormhole or something).