Require

[ROBINDESBOIS]

The president required the money be paid at once. Is it Ok without to in front of be paid?
THe president required that the money be paid at once?

[Rusty]

Both proposals are correct.

[ROBINDESBOIS]

and the money to be paid at once?

[Rusty]

It is OK without the 'to'.
You can include it if you want, but it makes no difference in the meaning.

I prefer the inclusion of the conjunction 'that' (the one found in you're last proposal), but this conjunction is often omitted in American English. I believe I like it because it's used in the Spanish equivalent of this demand.