Weird sound and lack of power in first gear

hi, the problem i have is that in first gear the power has drastically reduced and as i pull of the sound the engine makes sounds like a turbo at high revs, until i get into the other gears which seem fine, also i dont seem to get over 2000 revs in any gear, the warning lights have been poping on and off for a while which i know i should have acted on, but if any 1 can help i will be very grateful.. cheers!