Where can i find more weapon schematics the only ones i can find are bottlecap mine , and rock it launcher and how many there are.

well the stuff areis the dart gun, nuka grenade, railway rifle, shishkebab, deathclaw gauntlet, bottle cap mine and the rock it launcher
there are 3 schematics per custom weapon

They are scattered around the wasteland, some can be bought from vendors, some are given as quest rewards, some are located in buildings and some (or just one? not sure...) is just lying on the ground (fairly easy to miss).

Here's a complete list: http://fallout.wikia.com/wiki/Fallout_3_crafting#List_of_schematics

It's advisable collecting the caravaners schematics as soon as possible. They will most probably get killed by raiders or critters before you reach level 10, and finding their dead corpses out in the Wasteland isn't easy.