To answer the first part of your question, Queen's last performance with Freddie was Knebworth Park in summer 1986. The second part of your question i'm not too sure about, are you asking what time he died?

He died at approximately 18:42 that day

http://www.youtube.com/watch?v=QFLu6bu7LEk

"Mercury's final live performance with Queen took place on 9 August 1986 at Knebworth Park in England and drew an attendance estimated as high as 300,000." "According to his partner Jim Hutton, Mercury was diagnosed with AIDS shortly after Easter of 1987.[50] Around that time, Mercury claimed in an interview to have tested negative for the virus. Despite the denials, the British press pursued the rampant rumours over the next few years, fuelled by Mercury's increasingly gaunt appearance, Queen's absence from touring, and reports from former lovers to various tabloid journals. Toward the end of his life, he was routinely stalked by photographers, while the daily tabloid newspaper The Sun featured a series of articles claiming that he was seriously ill. On 22 November 1991, Mercury called Queen's manager Jim Beach over to his Kensington home, to discuss a public statement. The next day, 23 November, the following announcement was made to the press on behalf of Mercury: Following the enormous conjecture in the press over the last two weeks, I wish to confirm that I have been tested HIV positive and have AIDS. I felt it correct to keep this information private to date to protect the privacy of those around me. However, the time has come now for my friends and fans around the world to know the truth and I hope that everyone will join with me, my doctors, and all those worldwide in the fight against this terrible disease. My privacy has always been very special to me and I am famous for my lack of interviews. Please understand this policy will continue. A little over 24 hours after issuing the statement, Mercury died on 24 November 1991 at the age of 45. The official cause of death was bronchial pneumonia resulting from AIDS." Source and further information: http://en.wikipedia.org/wiki/Freddie_Mercury "Barcelona The song was composed by Mercury and includes violins by Homi Kanga and Laurie Lewis, cello by Deborah Ann Johnston, horn by Barry Castle and percussion by Frank Ricotti. It was written to be the theme song of the 1992 Summer Olympics in Barcelona, but Mercury died less than a year earlier. It was however performed live at the opening by Montserrat, with Freddie's voice recordings and it was used as the title music to the BBC's coverage of the 1992 Summer Olympics. The music video was filmed at the world's largest nightclub, Privilege in Ibiza." Source and further information: http://en.wikipedia.org/wiki/Barcelona_(album%29 "Barcelona", as seen in the video, can also not be considered to be a public performance. http://www.break.com/usercontent/2008/4/Freddie-Mercury-Last-Performance-483243.html Further information: http://www.findadeath.com/Deceased/m/Freddie%20Mercury/freddie_mercury.htm "Freddie Mercury Last Appearance 1990" http://www.youtube.com/watch?v=LeSvPDAi4l8

So sad to think of all the people who died before ARVs were invented.