Throat, ears and head hurts, still have some cefprozil 500mg (8 pills left) -- can I take them stil?

May not help. If your only issue is pain then your best bet is something like advil or tylenol (acetaminophen). Pain, generalized in the head as you describe, may be viral and antibiotics don't help viral illnesses.
Don't self medicate. The short answer is no... The long answer is that your ear, nose and throat hurting may just be a viral infection which is not treated with antibiotics. If it is bacterial and you take the Cefzil (cefprozil) for 4 days (twice daily) with 8 pills left you may under treat something. Best to be checked. If symptoms are less than 7 days - likely a cold. If greater than 7 days ... Likely a sinus infection.