now you can take your soldering iron (plastic welder ,i call mine the BCC 3000 .lol )its an 80 watt iron made by weller and i had one for 3 years and only gave up when i got it wet.I bought a new one for $40 and its gone left on overnight (oops) and will not burn out and should last another 3 years.plastic welding is pretty easy ,you basically heat the plastic like a tig welder and melt it into itself .You also use any scrap cut up pieces for filler pieces or as a rod to re-inforce welds.very important to do both sides and make sure you get really good penetration on both sides and not get too much heat into the panel to keep it from warping .Also more important is to test the weld after youve done it ,to make sure its strong ,it should be able to flex much more than its intended purpose and if it fails ,do it again until it doesnt or one day if will fail under the paint and its too late then.make sure you go plenty PASt the end of the crack on both sides .penetrationnow for the other side ,weld it and then add re-inforcement in the form of another piece and makse sure to make the outer edge of the crack with a lot of material to keep it strong or it will rip in the same place under stressit aint pretty but it will look better in a minutefor a crack this large ,dont try and do it in one shot ,tack it at both ends ,and then tack some more until its in its place and then join the tacks until the crack is fixed.