White blood counts 12.7 and red blood counts 4.5, what does it means?do i have leukemia?

Unlikely : Your question provides incomplete data so the answer is tentative. A 12.7 WBC corresponds to a 12, 700 per cubic millimeter in us jargon. The 4.5 would correspond to a 4.5 million red cells per cubic millimeter. Both of these numbers fall within normal limits.

VERY VERY UNLIKELY: One can say for sure that you can not diagnose leukemia based on these two tests normal white blood ceels count is 4.5 to 10000wbcs/mcl. Your count is slightly high which can be due to other conditions like infection and your red blood count 4.5 millions is normal.Normal values are 4.2to 5.4 milions cells/mcl also we do not know what differential count is and what the blood smear shows. Consult md.