In English we have to make the verbs agree in time in the same sentence. If we understood that "read" as past tense, the second verb should also be into past tense, otherwise the beginning has to be "am reading" since it's not usual to use "read" into simple present in a sentence like this.
So, the line could be either:
"I'm reading in the newspaper that you have a piece of land for sale."
or
"I read in the newspaper that you had a piece of land for sale."