342325 optimize joomla queries

i have a joomla 1.5.3 site running in php 5.2.9 and mysql 5.0.81 ...i get around 18-20,000 visitors a day (300-350 at a time) and growing steadily, since there were load issues as mysqld was causing over 35% load most of the time. My VPS RAM - 1.5 GB GARUNTEED (3 GB BURST). The main thing causing problems i believe are slow queries which do not use indexes/proper indexes ..many scripts said that many JOINs couldn't use indexes properly, so i want a person who can optimize my indexes and queries for optimal performance! (i have the mysql slow query log to help) ...also over 42% of the temporary tables were created on disk, even after i kept increase tmp_tables_size in [login to view URL] which leads me to believe this is because of BLOB and TEXT columns, so this is part of fixing/optimizing queries and indexes! please don't bid ridiculously high! don't bid if u dont have sufficient knowledge or don't believe you can do this 100%, i will only fully pay once i can see(through tests) that ur optimization has worked!