Suggest some methods for measuring AC current
If you have space on the board for an 8-pin SOIC, you can use the Allegro ACS712x20 for current sensing. 

It is a Hall-effect-based linear current sensor IC that can directly sense up to 20 Amperes, bidirectional current, with no additional components (current transformers etc) required.

It has 2.1 kVRMS minimum isolation voltage between sense line and signal output, and generates an analog signal proportional to magnitude and direction of sensed current. Resistance of the sensing path is 1.2 milliOhm. No external shunt resistor is required.

More information on the Allegro site.