How many miligrams is equivalent to 2+ range of protein in urine and what is this a sign of?

100mg/dL. 2+ proteinuria is equal to 0.5-1.0 gm protein loss in 24 hours. It is generally as sign of renal glomerular damage. This degree of proteinuria ought to be addressed with your doctor to start intervention to prevent further kidney damage.
Proteinuria. You cannot predict the amount of protein based on a 2+ reading on a dip stick. Proteinuria (p) is not constant. If you have 1 gram of p/day, that does not mean you have 250 mg of protein in your urine every 6 hours. You need to have a 24 hour urine collection for protein to see what amount of protein is in your urine on that day. See a nephrologist, and get one ordered to answer your question.