Water is getting in the oil, just put on a new water pump. What can be wrong now?

What is your question?

Just started last week. Leak under van replaced water pump, changed oil and filter. Looks like oil may have some water in it. Checked engine cold it's ok, after running for a few minutes looks like may be water in it.How can we find out what's wrong without costing an arm and leg. We're on a fixed income.