Move the phone base. Or look for a 900 MHz DSS model. Most are discontinued, but I think they'll be making a resurgance once everybody figures out that 2.4 GHz is, in many ways, worse than 900 MHz for cordless phones. IMHO, 2.4 GHz is a selling gimmick that feeds off the "bigger and newer is better" perception of the "average consumer." In other words, they sell for more money, and Best Buy makes a bigger profit from them. Best Buy really makes an incredible profit simply by excluding certain types of things from their stores. For example, all the 900 MHz phones are analog. Another example, in their computer department, a sales droid told me that everyone was moving away from stand-alone fax machines, and I would need to buy a $300 all-in-one machine. Needless to say, I didn't "buy" it.
I just ordered a refurbished 900 MHz DSS Uniden phone, with answering machine, for under $40. My old 900 MHz digital phone is still fine, but I've wanted one with a headset jack for awhile now. I hope it shows up soon.