I was in a similar situation as you a couple months ago.. What I would suggest is buy a stand, umbrella holder, and an umbrella.
the rest depends on your budget.
you have a bunch of options in stands and accessories, but here are a couple.
You want a portable light stand.
$19.95 = http://www.bhphotovideo.com …5_Light_Stand_Black_.html
you need a umbrella mount & a hotshoe adapter to set your flash on for the stand
$13.95 = http://www.bhphotovideo.com …117_Umbrella_Bracket.html
this one comes with both.. if you buy another model make sure you get the hotshoe mount also.
and an umbrella
$24.95 = http://www.bhphotovideo.com …Umbrella_Collapsible.html
I would get a simple setup something like that
the only problem you have is that the 430 does not have a sync port. Also, not sure which camera you have, So as far as remotely triggering the flash you will have to look into that.
anyhow what i did was experiment with my 580 EXII flash and stand for a little bit... then I considered buying another flash or two, but I started adding everything up and the cost was nearly what a set of alien bees would cost me... I ended up speding more, but got more power than 10 580 EXII's would give me now...
I also bought the ebay remote flash triggers for my flash.. they were nice to get a feel for off camera flash, but they fired allot on their own, so my batteries drained pretty fast. I ended up buying a set of pocket wizards, they work great, plus they have a $25 mail in rebate going on for a couple more weeks on them.
I would say spend the least amount to experiment with off camera flash, then you will know the next step you want to take..
I would also recommend reading Light Science & Magic. I bought it a couple days ago, and I am almost half way through it, and have learned a great deal about light already.
goodluck.