I have been going consistently to the gym on my lunch hour for 2+ months now at 4 times a week.

I usually do 20 mins crosstrainer, 10 mins running, 10 mins rowing- sometimes I do the bike or crossramp instead of running and rowing.

It never seems to make a difference though!

I realise diet has a huge part to play and mine isn't the healthiest but I should still see some benefits surely?

Can anyone recomment a routine to help me lose weight based on going to the gym 4 times a week?
Should I do some weights as one of my trips?

I'm thinking of now doing step/toning classes twice a week and cardio the other 2 times?

HELP!
Any advice is welcome!

You answered your own question, diet.

Its funny really the more cardio you do the less effective it is because you body becomes use to it and is more efficient. That's why you see some instructors that are not all the lean.

Weight train to build some lean muscle mass to increase your metabolism.

thanks-will try the weights instead of cardio for a few sessions!