Since you have a converted system, now would be a great time to go to a parallel flow condensor. They are not very expensive and will add cooling capacity to your converted system.

You can get them from several sources. Go to www.aircondition.com and you will find a link to Carlisle and ACParts.com, both good sources. Any auto ac shop can install and make the hoses if necessary.

Be happy that the problem is the condensor and not the evaporator.

Good luck,