unprotected sex----in need of advice

on 4 February, i had unprotected vaginal sex with a thai sex worker for less than two minutes.
within 24 hours i took Kaletra, lamivudine and zidovudine for 28 days.

on 30 March, this woman had Elisa test (IgG,IgM,IgA)with negative result.

does it mean i have little chance of being inffected?

Elisa test (IgG,IgM,IgA) is the third generation test,right?
so the negative result after 8 weeks is accurate, isn't it?

[oldskool80]

8 weeks -ve is unlikely to change...
but 12/13 wks is conclusive....