Database experts need - Consultancy

we have a pretty big dating site with php/mysql. our database reaches 2gb data and over 3 million records. we changed database structure 2 times when growing. but at last, we read many tutorials and optimise methods about mysql and we CANT HANDLE database now. got many problems with mysql: database down, data lost etc.. i think mysql is not enought for this work. i am thinking to switch it to another database software. i need know what must i do now? mysql is not stable now and we cant increase our member count. sometimes mysql down when site has 400 active users, sometimes down 800 active users. we need many recommendations about this matter and fix our database problems. but looking for cheap solution. i cant give 40k to oracle. maybe i have to switch to another dbase software or i use mysql cluster(i dont know what is that cluster thing). i need advices about all of these things... mysql version: 4.0.18-standart table type: myisam server: dual xeon 2.4ghz with 2gb ram i need **EXPERIENCED persons** to help me. everybody knows database using, installing, handling etc.etc. but i need a person who work with LARGE database developments like hosting huge data and serving 1000s of users online. i dont need knowledge, i read tons of tutorials and apply them. experience is better to go forward now. ## Deliverables 1) this is like chatting. i will ask some questions and get responces with your comments. 2) i send database structure and get some ideas. ## Platform redhat