Finishd Comp May'15 compltd 12 mos on OPT appld for 24 mos OPT-extn in May'16 Whn shud my co. stt appling for h1b?

Finished my under graduate Computer Science from the US. Graduated in May 2015. Currently on OPT status. Applied for opt-extension. Working full time in California as a Jr Software Development Engineer. Want to know when my company must apply for H1B

You can avail 36 months of OPT, which takes you through May 2018. So H-1 can be applied in April 2017 and April 2018.