Can you get the artificial horizon back? No. With your last remaining engine gone so went the generator supplying electrical power to keep the instruments gyros energised.
In this case you should have gone to limited panel; use your Airspeed Indicator, Vertical Speed Indicator, Compass and Turn and Slip indicators, scanning each for a second in swift and regular pattern to try and inform you what the a/c is doing.
It's called flying limited panel and is very hard. It will take practise.