I would not attempt giving it anything other than 19V power supply. The amperage of the power supply, as long as equal to or greater than, wouild be ok (electronics only use what they need). The device wants 19V and that is what it was designed for, any more or less and you are asking for problems.
The voltage has to be the same. So you need a 19V power supply. The current has to be the same or greater, so 4.74A or more. You also have to ensure the polarity is the same. Some barrel jacks have center pin positive, some have center pin negative.
If you're not comfortable figuring this out on your own, I'd just get a new official supply. You can easily fry your light if you don't get these numbers right.