Import package Path issues in Go

I am trying to build a collections package in Go, and I am having trouble with import paths.

I am modeling the Java Collections interface. Here is my file structure

+/$GOPATH
    /bin  
    /pkg  
    /src  
        /github.com
            /user
               /collections
                   collections.go
                   main.go
                  /collections
                      /bstAvl
                         bstAvl.go

My collections.go file looks like this:

package collections

type Collection interface {
    Add(interface{}) (bool, error)
    AddAll(Collection) (bool, error)
    Clear()
    Contains(interface{}) (bool, error)
    Remove(interface{}) (bool, error)
    Size() uint
}

In bstAvl.go i am trying to use the Collection interface in Collections.go

How do I import the required package to access the Collection interface?

I think I have gone overboard with the paths, probably made it more complicated than it should be. Is the simpler structure you recommend?

Ideally, I would want all my collections to be under the collections package so that it could be exported as a library and used in other applications if need be.

P.S I have read Structuring applications in Go by Ben Johnson. But I am still confused. Any help is greatly appreciated.

EDIT:
I guess i over worked the package structure. I have decided to stick with this:

+/$GOPATH
    /bin  
    /pkg  
    /src  
        /github.com
            /user
               /collections
                   collections.go
                   main.go
                   bstAvl.go

To import collections inside bstAvl.go, use the full path:

import "github.com/user/collections"

When it comes to structure, it all depends on types of package, and I do not know Java collections enough to give advice in this specific case.

However, to avoid getting a repeating collections/collections, I would suggest placing the bstAvl folder directly under the initial collections-folder:

+/$GOPATH
    /bin  
    /pkg  
    /src  
        /github.com
            /user
               /collections
                   collections.go
                   main.go
                   /bstAvl
                      bstAvl.go