Sometimes you can change the order, and it would be all right to do so in this sentence, but it's not the usual order.
The usual order is
place, and then
time, if you're
putting them at the end of the sentence. This order is fairly strict
but not absolutely required. Prepositional phrases, like
with his girlfriend, are a little more free to move about.
We are going to New York next month.
We are going with our relatives to New York next month.
We are going to New York with our relatives next month. <
We are going to New York next month with our relatives.
I saw a friend of mine at the mall yesterday.
I saw a friend of mine with his girlfriend at the mall yesterday.
I saw a friend of mine at the mall with his girlfriend yesterday. <
I saw a friend of mine at the mall yesterday with his girlfriend.
(< shows my preference.)
CJ