How to file government appeal in High court other than private appeal

Sir. My sister was murdered for want of dowry in 2013 at Allahabad. In which her child was main eyewitness and also there were many documentary evidence against accused but after 4 years trial in district court allahabad the judge pronounced the order in favour of accused .The trial court pronounced 7 years imprisonment to main accused in ipc 306. Instead of 304B and 498 etc and no punishment to other two accused. And now the accused filed an Criminal appeal to Allahabad high court against his punishment under section 306. On our side we approached to Government advocate of district court and told him to file government appeal against trial Court judgement then he strongly denying that i can not file Government appeal because this judgement is sufficient. After that we approached to DGC trial court for government appeal ; he told that i will file but still after 40 days of decision he did not filed. Sir i want your valuable opinion; how can i do to file government appeal now???