True 128bit secured password length? assume we say 128bit keys are secure so a 16 character long password is safe, but if i even use lower case and upper case letters with numbers and special characters on my keyboard its about 80 different character i can choose, as we have 256 different byte in nature so it look like the 16 character random password i choose is about a 60 bit secure key ... ?!
how to fix it and what is secure length to use ?
If your alphabet (set of all possible characters) has size $s$ and your password has length $l$, a randomly generated password has a strength of $\log_2s^l = l\cdot\log_2s = l\cdot\frac{\log_{10}s}{\log_{10}2}$ bits.

This means if you want to create a 128-bit password using a 80-character alphabet, you need at least $\left\lceil128\cdot\frac{\log_{10}2}{\log_{10}80}\right\rceil = \left\lceil20.25\right\rceil = 21$ characters.

In practice, humans aren't very good at creating random passwords; and the greater the alphabet gets, the greater gets the bias. Non-random password (e.g., sets of dictionary words) are even worse (as low as 1 bit of entropy per character).

If possible, you should generate your passwords randomly (with a program, not by hand) and store them with a password manager, or use a KDF (as Thomas already suggested in the comments). Trucrypt actually uses PBKDF2 for key derivation. (source)