My account was at Level 2, but why I'm at Level 1 now..?

Usual reason is that a game you gave away was in a bundle or at a very high discount, which, at the time, was not shown like that in the Bundle List, but has since been added (and is backdated to the date it started at the discounted price or bundle) and so you only get the 15% value.
The other big reason is, a giveaway game has been made cheaper (permanently) on Steam.

The value of a game you gave away probable went down or it got bundled, meaning it's now worth 15% of the store price.

It's happens to everybody incl. me. If u really wanna now, keep track of your GA incl. price in a Spreadsheet, today one of my GA game drop from $15 to $10 on Steam.

Off-topic : I don't know if giving away game that you won from other site is allowed here..
On-topic : No idea

http://www.sgtools.tk/nonactivated/LorenzoAndre/76561198018303762

i got gifts of penny arcade 4 that costs 0 points...so dunno :p.