You may have several options, some dependent upon which of the wireless carriers you use. (which one, btw?)
These two solutions are carrier agnostic (with appropriate models for various cell phone technologies/frequency bands/carriers)-
Repeater/amplifier (either whole house/whole-multiple room)-
There are desktop versions, but these are generally not going to perform as well as the models that require an external antenna. Of course mounting an antenna on an external roof or space may be required to get a service to perform how you want it, and this adds to the overall cost including wiring.
Some folks have used the Wi-Ex indoors to help cover at least part of a house or office-
So ballpark you will start at around $299, upwards of $500+ for the Wilson solution with an externally mounted antenna.
If you are lucky, your wireless carrier offers an indoor solution that they provide for customers in fringe reception areas. ATT just started rolling out microcells (femtocells) which bascially connect via your broadband router. This is only an option if you have high speed internet at your vacation home. Sprint & Verizon offer similar devices for their customers. This would be cheaper than the above amplification solutions w/ external antennas. Consult the carrier web sites for more details.
There have been some previous threads on this topic if you look back over the last year or so.
I want to get rid of my land line in a winter vacation home but the cellular signal strength inside the home is poor (typical Florida metal roof and metal siding!).
All the previous posts are very old and there must be new technology. I've found quite a few via "Google-TM" searches but would like the opinions from people who have direct experience with cell phone signal boosters in homes.