Transparent shader

Hi,
i need to make a shader that has place for a diffuse texture, normal and specular and that takes the transparency from the alpha. The problem is that the shader that comes with unity, cut out, makes it 100% transparent only.

Is it possible to have only 50% of transparency taken by the alpha channek of the RGB?
I found this shader but it makes all the object transparent, not just the part of the alpha. Is it possible to tweak it?

Shader "Custom/Glass"
{
Properties
{
_Color ("Main Color", Color) = (1,1,1,1)
_SpecColor ("Specular Color", Color) = (0.5, 0.5, 0.5, 0)
_Gloss ("Gloss", Range (0.01, 1)) = 0.5
_Shininess ("Shininess", Range (0.01, 1)) = 0.078125
_MainTex ("Base (RGB) Trans (A)", 2D) = "white" {}
_BumpMap ("Normalmap", 2D) = "bump" {}
}

SubShader
{
Tags { "Queue" = "Transparent" "IgnoreProjector" = "True" "RenderType" = "Transparent" }
LOD 400

CGPROGRAM
#pragma surface surf Lambert alpha

sampler2D _MainTex;
sampler2D _BumpMap;
fixed4 _Color;

struct Input
{
float2 uv_MainTex;
float2 uv_BumpMap;
};

void surf(Input IN, inout SurfaceOutput o)
{
fixed4 tex = tex2D(_MainTex, IN.uv_MainTex);
o.Albedo = tex.rgb * _Color.rgb;
o.Alpha = tex.a * _Color.a;
o.Normal = UnpackNormal(tex2D(_BumpMap, IN.uv_BumpMap));
}
ENDCG

CGPROGRAM
#pragma surface surf BlinnPhong finalcolor:final decal:add

sampler2D _BumpMap;
half _Gloss;
half _Shininess;

struct Input
{
float2 uv_BumpMap;
};

void surf(Input IN, inout SurfaceOutput o)
{
o.Gloss = _Gloss;
o.Specular = _Shininess;
o.Normal = UnpackNormal(tex2D(_BumpMap, IN.uv_BumpMap));
}

void final(Input IN, SurfaceOutput o, inout fixed4 color)
{
// Need to set alpha here rather than in surf to make this work with all lights
color.a = 1;
}
ENDCG
}

FallBack "Transparent/VertexLit"
}

 

Unity 5, the standard shader, can do what you need it to do with 0 shader writing.