I haven't seen any 3G stick, that wouldn't support EDGE or HSP(D)A so far but even if you found such an old and presumably clunky device, I doubt it would bring any improvement because EDGE and HSP(D)A automatically fall back to GPRS and UMTS as soon as too many transmission errors occur. Further such an old 3G stick would have an outdated, less sensitive RF-chip lacking diversity-support, so you would probably end up in even worse reception. You should rather look for a modern device with RX-diversity support for those 3G frequencies you actually intend to use, because often diversity isn't supported for all the 3G bands of a multiband device. However the most effective measure remains an external antenna - so perhaps also look for a device with antenna connector. I would recommend a Huawei E176, which you might get relatively cheap from eBay Germany, where they sell the T-Mobile branded (but unlocked) version designated "Web'n'Walk Stick IV", which definitely supports 3G at 850, 1900 and 2100 MHz - all with diversity:
http://shop.ebay.de/i.html?_nkw=web+...t=PCMCIA_Cards