when i was pregnant with my first daughter i needed to get in to shape... so i did hirea trainer, but what i did was only meet with her ever 4-6 weeks. so she would set me up with a routine, then tweek it every so often. it wasn't nearly as expensive... and had the added benefit of being a motivating factor because one... i'd still see her at the gym at least weekly... and i would know i'd have to admit i wasn't exercising if i hadn't been going in between our sessions.
another idea, my friend does.. she looks up diff routines on-line or in magazines.... then does that routine for 4-6 weeks, then switches to a new one... keeping, adding, deleting exercisrs she likes or doesn't like. also, try different classes... even things you never thought you'd like... it keeps things interesting.