Buy another gun. Probably not a lot more expensive than a conversion, anyway.
I bought a Blackhawk Convertible a while back mostly for shooting 9x19 in. I must admit, it's a versatile gun for me and I like it a lot, but not exactly a light DA carry.

I might carry it occasionally, though, when our new open carry law goes into effect next month. Won't exactly be a regular deal, though.
I'm not sure why you want a .357 in an LCR, though. Yeah, it's capable of a bit more, but 9x19+P is a pretty decent round, certainly hotter than .38 special, and the LCR has the advantage of moon clips.

But, there are other reasons that are more esoteric, I understand. Reason for my Blackhawk was simply that I wanted to have it in 9x19 because I have a Dillon progressive set up for the specific caliber. It's fun to plink with when it's tough to find .22 and even factory ammo isn't expensive. BUT, now I'm finding more and more .22, still like the gun, though.
And, may the Lord bless you, too.
