Dragon Ball Z: The Legacy of Goku II

Here's the location of the Nameks:

#1 - The left side of Kami/Dende's Lookout.

#2 - In the Kitchen of the Mayor's House in West City.

#3 - In Apartment B of West City (Fourth Floor).

#4 - Around where you went to fought Cell at the Tropical Islands. There is a
bridge there. Head across to get to him.

#5 - In the most Northeast portion of the area behind the level 30 Vegeta
gate in the East District 439. Skim along the trees to find a secret
passage.

#6 - In the Northern Wastelands. Turn on the switch behind the Goku gate to
open up the bridge and get em'.

#7 - Behind the Level 30 Piccolo gate in the Northern Mountains.

As for getting Mr.Satan, you need to level up Piccolo, Vegeta, Gohan and Trunks to level 50, then destroy the lvl 50 gate that belongs to each character (And get the statue inside each area after breaking the gate). The best place to level up is The Snowy Highlands, and here's the location for each gate.

Gohan: Go to Gingertown. Go left to the woods, then up 2 screens. You should
see his level 50 gate, beat it to get his statue.

Piccolo: Go to new namek. Head north and find his gate, beat it to get his
statue.

Vegeta: Go to Norhtern Mountains, to the place where the Force-Barrier blocked
entrance to Gero's lab was, go left and see his level 50 gate, beat it
and get the statue.

Trunks: Go to Triceratops Jungle south of west city. Go right and find the
gate, beat it and get the statue.

Hope that helps. If you still have trouble, try using one of the FAQ's for help/