At this point in time you shouldnt be worrying. Enjoy whats to come and deal with a move back to the US when and if it comes. As missy says, there are a few ways to get yourself and your husband back to the US if you want to. So much can happen in two years, who knows it might even be 4 years or 6 months! The way the rules and regs are changing minute by minute (it seems) now days, you'll just have to wait and see what you need to do when the time comes.
At the moment (Spring 03 - 04), a household size of two needs to show $15,150 in income (via tax returns, current US jobs, firm US job offers, and/or jobs abroad that will continue while in the USA - the particulars arent important). If you cant show that then you'll have to have some assets. The assets will have to equal five times the difference between your household requirement and your income as shown on the most recent tax return.
They do not ask for information on debts, only outstanding balances on mortgages for property that you own. So everything that shows a positive balance (savings accounts and investment accounts as well as profit from sale of houses and cars or other assets) is free to use towards your requirement.
That figure will surely go up in the next few years thanks to our little friend "inflation", so really you cant even begin to estimate what youre requirement will be and what you'll need to have by way of income and/or assets.
Your parents can act as co-sponsors if they have enough assets/income to support a household size that includes both of them, any dependants or people living in their house, you and your husband. If you dont live with them you may be able to exclude yourself from the household size, but your husband cannot be excluded weather he lives with them or not. For all I know the rules could change in 2 years and all of this wont apply anymore.
You just have to wait and see. Its nothing to be scared of and is actually a lot easier than it looks when all you see is people asking really specific questions about something that doesnt apply to you yet. It looks overwhelming and sometimes it is, but its nothing that should worry you now. If you ever want to return to the states, there's always a way.
For now - enjoy your life in England.