heavy cream and half-and-half substitute I am trying to make ice cream and it calls for 3 cups half-and-half and 1 cup heavy cream.

I don't have either but I do have one gal of 2% milk

If I can make some half-and-half and heavy cream out of it that would be awesome or if you know a good substitute for both that would be nice too!

UPDATE :
Full recipe

"Ingredients

3 cups half-and-half

1 cup heavy cream

8 large egg yolks

9 ounces vanilla sugar

2 teaspoons pure vanilla extract

Place the half-and-half and the heavy cream into a medium saucepan, over medium heat. Bring the mixture just to a simmer, stirring occasionally, and remove from the heat.

In a medium mixing bowl whisk the egg yolks until they lighten in color. Gradually add the sugar and whisk to combine. Temper the cream mixture into the eggs and sugar by gradually adding small amounts, until about a third of the cream mixture has been added. Pour in the remainder and return the entire mixture to the saucepan and place over low heat. Continue to cook, stirring frequently, until the mixture thickens slightly and coats the back of a spoon and reaches 170 to 175 degrees F. Pour the mixture into a container and allow to sit at room temperature for 30 minutes. Stir in the vanilla extract. Place the mixture into the refrigerator and once it is cool enough not to form condensation on the lid, cover and store for 4 to 8 hours or until the temperature reaches 40 degrees F or below.

Pour into an ice cream maker and process according to the manufacturer's directions. This should take approximately 25 to 35 minutes. Serve as is for soft serve or freeze for another 3 to 4 hours to allow the ice cream to harden.

Recipe courtesy of Alton Brown, 2005
"

edit 

i don't want a full substitute like almond milk and coconut cream
i can use butter ect
Cream has a high fat content, fat adds elasticity, flavor and a smooth mouth feel to ice cream. You can use 2% milk in ice cream instead of cream and it will work, however it will not have many of the desirable properties you get from cream. It will be harder and taste "weak" for lack of a better term. 

If you want to make a lower fat ice cream then you can make up for the lack of milk fat somewhat by using more egg yolks and adding stabilizers like xanthan gum, guar gum, etc. See my answer to this question for a bit more detail on gums in ice cream.

It is possible to make a cream substitute by mixing 1/3 cup melted unsalted butter with 3/4 cup milk, but this would only work for recipes where the emulsion of fat in the liquid is not required - all you will get from this is milk with fat floating around in it. This may work in some baking applications, but it won't whip and it won't make ice cream you'd want to eat.