All cars have keyless entry. It's called a brick through the window.
Go the dealership - they will have to "program" a new key and / or remote for you. They should be able to do it same day but it may be a little pricey.
If you want to opt out - go ahead and purchase a new security alarm. They come with keyless entry, remote start, paging, even camera's now. Here is an Amazon link of a SCYTEK (one of the best out there) to give you an idea.