Hey, if you'd like I've got 2 pair of Kenwood 2-way 6x8s which would drop right in. You can have both pairs for $40 + shipping.
There are better speakers out there, but these are [very] inexpensive

, easy, and a good step up from stock speakers. They'll run very well off just a HU too.
For a very good HU, check out this
JVC KD-SH55 for a very nice HU for $180.
UPDATE: Speakers are sold.