New player looking for tips on Artificer in 3.5e

[SasaeTsuriKomi]

Hello! I'm currently playing a 3.5e campaign with a bunch of the experienced players that we plan to do a very long campaign.
I've decided to pick to play Artificer, due to the item creation system seeming really cool (it's so good in comparison to 5e! I can just say I make something, do a roll, and make it!) and the fact that I really enjoy playing support characters.
I've been having good fun so far, and I understood that I would be worse of in combat, but I underestimated by how much. The best I can due is give some basic buffs before combat, and during combat either staying defensive or do comically small amounts of damage with my crossbow (poor + to hit and only d8). I'm looking to change that.
So, how can a level 3 artificer improve himself a bit? Wands seem like a good pick, but I don't know what kind of spells to look for.
Also, since this is a long term campaign, do you know any good prestige classes for artificer? We aren't picky with our sources, but the only thing I found is High Handcrafter.
Any advice would be appreciated!

[Bohandas]

For combat a wand of magic missiles would probably be good. At higher levels you're gonna want to upgrade that to a wand of fireballs.

[ExLibrisMortis]

Artificers are famously complex. I would recommend two guides:

The Complete Cost Reduction Handbook
Disregard Money, Acquire Buff Spells

The former is on improving your crafting, the second is almost entirely about the spellcasting side of the artificer. At higher levels, it's helpful to create a spreadsheet to keep track of your crafting (and possibly your buff spells, too, if you're into that sort of thing).

At level 3, you can expect to be fairly weak for a while yet. Spellcasting-heavy builds are generally slow to mature.
Once you hit artificer level 5, you'll get third-level infusions, including metamagic item, which allows you to apply Persistent buffs, including e.g. swift haste and heroism. With those, you can be effective in combat, although it'll cost you some XP.
You get access to both fourth-level infusions and polymorph at level 8. At that point, you can have high stats for cheap, and your combat performance will be quite high (though note that polymorph cannot normally be Persisted). I would recommend the bladerager troll (MM5 p. 180) as early melee brute form.
At higher levels, war troll (MM3 p. 181) is a very good melee form because of Dazing Blow. By the time you get to that, you should be able to supply high-end custom items to the party, and you can start thinking about building e.g. airships (they make a good party base). See if your DM won't let you use Landlord (Stronghold Builder's Guidebook p. 10) to pay for extra-large (and extra-luxurious) airship.

Have fun, and don't spend all your XP on buff spells! Wait until level 8 to go completely nuts.