I know I need more ventilation but???

So my house currently has no sofits (only facia boards) with no intake vents and 3 gable vents. So I know I'm in desperate need of ventilation but I'm not going to be able to re-roof and straighten it all out till hopefull next year. Just don't have the money right now. Are there any solutions that will help till I'm able to have it done right? All the facia vents I've found require taking shingles off and I don't intend on doing that till I re-roof. I've been working on the insulation in my knee walls and have removed all the insulation that was stuffed in against the facia boards and I can see light though seems where the board meets the house so I know some air is getting in now so it has to be better then is was. The ice dams I had last winter were about 2 ft thick and I was really suprised they didn't bring the gutters down. And during the summer the 2nd floor gets so hot you can stand being up there during the day.
So are the air gaps I opened up by moving insulation enough to feed 3 gable vents to do the best job they can for now or is there something I can do to get by till I re-roof?
One suggestion I was giving was to get a gable fan but if there's not enough intake air wouldn't the fan just pull conditioned air out of the living space where ever there are leaks? From what I've read thats something to avoid.
I know the permient fix is ridge vents and some type of intake venting but that's still awhile off.
Ideas?