I recommend watching this film
It does not feature authentic aircraft but the war and people look authentic (a bit idealised of cause). If you like it I can find 1-2 more probably.
As a child I was reading memoirs of
Pokryshkin,
Kozhedub, Golubev (about Pokryshkin),
Most of these memoirs are not translated into English yet. You can find a couple of memoir books on amason though. Also there is a series on soviet aces published. Try googling "soviet fighter memoirs" and\or "vvs aces memoirs". Most of these books were published during soviet times and you have to skip some propaganda pages when reading.
Vasily Grossman's
Life and Fate banned and confiscated by KGB it was secretly taken outside the USSR, published in the west, then dramatised on BBC radio and even
made UK best-selling lists. It is about the most ruthless battle in the history of mankind - Stalingrad (Germany - total 841,000 casualties, USSR - total 1,129,619 casualties). If you want to read one book about the Eastern front (or about any war in general) I recommend this one. It is not the shortest but it is worth reading even in small portions. One of characters is a fighter pilot too.
Wiki article on Life and Fate
http://en.wikipedia.org/wiki/Life_and_Fate
Since La-5 was first introduced in Stalingrad I guess it can be the next theatre in the Il-2 series.
Regarding Eastern Front role in the war in general estimated Nazi losses on Eastern/Western front are 4,428,000 to 5,178,000+ for Eastern / 997,386 to 1,000,256 for Western according to English wiki (I know this is not 100% reliable). I think aircraft and armour losses are more or less proportional to some extent.
http://en.wikipedia.org/wiki/Eastern...orld_War_II%29
http://en.wikipedia.org/wiki/Western...orld_War_II%29