What Leith said.

Without being judgmental, you might want to brush up on regular Excel concepts before plunging TOO deeply into VBA. In particular, I would study the syntax of an IF statement in Excel and see if semicolons are explained. (Have you used another language that uses semicolons for IF statements?) Another item you might want to get comfortable with is using double quotes in a string. Here's a good explanation specifically for doing that in VBA: (Oops, I can't post URLs here[yet] - google the next line.)
site:vbaexpress.com What is escape character for quotation marks?

Why you are trying to use .FormulaR1C1 instead of just ".Formula" ?

And the Rng assignment is very unusual looking. Are you trying to put the formula in all of [new] column AR except row 1, as well as a certain (or actually uncertain) number of cells in column B? That doesn't seem to relate to "Fixed Assets". It's hard to understand what you're really trying to do.