Oil Question

I currently have quakerstate high milage in my car and i need to top it up question is i have quaker state full synthetic from previous changes can i use that to top up or no?

If your in dire means, you'll have to better than runnin a dry motor.
but if you can make it to the store your best off using what you got in there.

ok thx its just that i have been told that it doesnt really matter as long as its the same make (quaker state) and same grade which is 5w30.
im not running extremely low so i guess it could wait till i get to the store.