Well, it looks like I get to disagree with a lot of people on the boards again. Sorry about that....
I leveled up just fine specced holy, dumping my first 31 points in to get to Holy Shock as quickly as I could. I've tried leveling ret, and for me it sucks. I die a whole lot more because I tend to burn out my mana doing damage, then have none to heal, and not particularly good heals even if I have the mana. Playstyles vary - if you like fighting in holy spec, do it. If you're getting bored playing your paladin and feel like it takes forever to level, then play with your spec, but if it ain't broke don't fix it.
For professions, I went mining/smithing - this was also my first toon, and yeah, I spent a lot of time without much money. But it was fun, I got to wear a lot of my own stuff, and when I needed money, like when I got to 39 and started thinking about a mount, it was easy enough to just farm Badlands for iron at 5g a stack for a while until I got it. Making money is easy, just do what you enjoy. For every other paladin I've tried to level, I've picked up engineering. It has some really nice things that you don't get as a paladin - ranged weapons, aoe, pets, crowd control - and it's just a blast.
As for the LoH, I've actually found that pretty useful. Back in the day when AV's ran forever, it was really nice having that "oh #$%#" button every 40 minutes instead of every hour, and it was really nice when our guild first broke into raiding. All the healers would go out of mana quickly the first time we fought a new boss, since very few of my guild were geared, and I got into a system of healing until I was oom, waiting for the tank to nearly die, then hitting LoH and potting up to heal again. By the time we fought our way through the trash to the next boss, the LoH was about ready again.
As for gear, the truth is there isn't much plate or mail available below 60 that's really going to help a holy paladin, and if you want it you're going to need to spend a lot of time farming cash to buy it. Almost none of it is quest rewards or easy drops. You really need some more +int in there to beef up your mana pool - I'm guessing you run out of mana pretty fast in a fight. Other than that, I don't see any real problem with your gear for solo work. It probably wouldn't help you much if you tried to heal groups, particularly as main healer at your level - if you've got the bag space and it doesn't get you into any loot fights, you might want to think about settling for some leather or cloth if it gives you really good +heal or +int. Or learn to use consumables - potions, scrolls and food can really beef you up.