I agree with Pam in that replicating the meal at home, for convenience and cost savings, would be the way to go, but I hear that you aren't too keen on that.
Don't get me wrong, I like Subway. But it's not as healthy as some make it out to be. For example, not one of their breads is whole wheat. I also came across this the other day: Subway Nutrition - Prevention.com
I agree that you have to do what works for you personally; I just hate to see you married to Subway (or any one thing) for the rest of your life. There will be more than one thing that works just fine, and nothing is a magic bullet. I don't really buy the "I don't have a choice" mentality. There are certainly more ways to lose weight than eating one specific sandwich every day!
The longer I've been conscious about my food intake, the more I tend to get bored with it. You may want some variety eventually, so have fun experimenting! We did a thread a while ago about What are you eating right now, and another, What's in your lunch box, that's more recent. Maybe take a search for them and see if you get any ideas. Try small changes and when you hit on something that works for you, you can include it into your repertoire.