How many weeks am I??

If my last period was on Sept 12th and I had a faint positive before my next period and took a blood test for pregnancy and got hcg level of 18.08, then started bleeding like my period. After AF was done and took another blood test after a week and got hcg level of 258.97, how far along am I? Help plz, I'm confused n this is my 1st time. TIA ♡