I use bisto powder as well.
I usually have some chicken or turkey stock in the freezer from things earlier in the year (maybe Thanksgiving, occasionally I still have stock from the previous Christmas turkey - I cook that on 26th Dec).
I also, if I need extra liquid, use the water from boiling carrots.
It's relatively quick to make the gravy:
In a bowl, put the powdered bisto and some cold liquid (stock, plain water, or the wine). Stir to combine.
You can then add this to the pot where you may have already heated the rest of the stock (be brisk with the initial stirring!) or it is still cold. Or you might be doing it in the roasting tin, if you have already got the turkey out and have space on your cooker to do that - and scrape up all the bits from the pan (but do pour off the fat before adding the gravy mix).
Stir through and heat to boiling, stirring all the time. I use a flat whisk for this nowadays as slightly easier, but the wooden spoon is what I was reared using and works fine.
Once the gravy has thickened, I tend to add my wine - a decent splosh to add flavour, and let it gently bubble for 2-3 minutes. And then add the meat juices from the turkey itself for extra flavour.