Depends what you consider winning..
My last winning streak was Thanks Giving weekend. I won about 900-1200 that weekend (hard to keep track of). But it was done in $250-300 amounts I'd go win 250 go back the next day win another 300 go back the next day win another 400..
My last BIG wins where around 3/2011. It started in Jan. I hit the ravens for the first time during a bonus around was 10,000x12 the bonus kept retriggering at least 10 times but I only won an additional $50-80 (wish I hadn't wont hte extra $50 would have saved me the hassel of dealing with taxes. That same night I was playing Ruby Slippers betting 120 or 200 credits a spin (can't remember the exact numbers) and got the first 4 reels wild with the 5x unfortunately it didn't line up any of the higher paying symbols so it was the 4 wild symbols x5! That night I walked out of the casino with around $2800 or so.
I went back about 3-4 weeks later and was playing the 3 reel WMS Fishing game. Betting 300 credits a spin I hit the bonus and won $1100 or so. After a few hours of play I was down to about $750 and walked to the high limit slots. A woman was playing $50 a spin on the I believe the name is Wild Water Aristocrat machine she got the bonus. This motivated me to put $100 in a $1 version of Norse Warrior had 10 lines. I could only stomach betting $10 a spin and hit the free spin bonus on the last $10 wich paid out about $1200. That night I walked out with $3800
A few months later I had been at the casino for about 4 hours and was down $700 I only had $100 left and figured I'd play a machine I never had luck seeing I was having no luck on machines I typically win on. Put the final $100 into $1 WOF Secret Spin. Hit the spin feature a few times winning between $250-300 I was up to $600 and hit it again getting 6x multiplier and $150.
Since then wins have been nothing more then a few hundred here or there.