Yeah, in all likelihood you are stuck at something akin to the regionals for a while. I would go find a guard/res unit to fly your arse off with until you have the competing times. Spend as little time as humanly possibly in the cesspool or regional airline flying. The good thing going for you is that pretty much all of your time is PIC multi, so all you really need to work on is total time...

As for corrections to time, eveyr airline has a different policy. Some multiply your total time by a factor like 1.2 or 1.3, some add .2 or .3 per sortie. There is no standard across the board, you have to find out what the company you are looking at prefers. Many of these conversions have been covered here in the forums already. Seraching will probably get you the factor said company uses, but I would still doublecheck to be sure.

For the ATP, you've gotta have the 1500. UNLESS you were to go back and create a logbook that has every flight you've ever taken and factored all the actual taxi times and what not and ended up coming to 1500. Probably not the best solution by any stretch but it would work.